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2020-07-30tracing/hwlat: Honor the tracing_cpumaskKevin Hao1-2/+3
In calculation of the cpu mask for the hwlat kernel thread, the wrong cpu mask is used instead of the tracing_cpumask, this causes the tracing/tracing_cpumask useless for hwlat tracer. Fixes it. Link: https://lkml.kernel.org/r/[email protected] Cc: Ingo Molnar <[email protected]> Cc: [email protected] Fixes: 0330f7aa8ee6 ("tracing: Have hwlat trace migrate across tracing_cpumask CPUs") Signed-off-by: Kevin Hao <[email protected]> Signed-off-by: Steven Rostedt (VMware) <[email protected]>
2020-07-30tracing/hwlat: Drop the duplicate assignment in start_kthread()Kevin Hao1-1/+0
We have set 'current_mask' to '&save_cpumask' in its declaration, so there is no need to assign again. Link: https://lkml.kernel.org/r/[email protected] Signed-off-by: Kevin Hao <[email protected]> Signed-off-by: Steven Rostedt (VMware) <[email protected]>
2020-07-29sched,tracing: Convert to sched_set_fifo()Peter Zijlstra1-25/+23
One module user of sched_setscheduler() was overlooked and is obviously causing build failures. Convert ring_buffer_benchmark to use sched_set_fifo_low() when fifo==1 and sched_set_fifo() when fifo==2. This is a bit of an abuse, but it makes the thing 'work' again. Specifically, it enables all combinations that were previously possible: producer higher than consumer consumer higher than producer Fixes: 616d91b68cd5 ("sched: Remove sched_setscheduler*() EXPORTs") Reported-by: kernel test robot <[email protected]> Reported-by: Stephen Rothwell <[email protected]> Signed-off-by: Peter Zijlstra (Intel) <[email protected]> Reviewed-by: Steven Rostedt (VMware) <[email protected]> Link: https://lkml.kernel.org/r/[email protected]
2020-07-27fsnotify: create helper fsnotify_inode()Amir Goldstein1-2/+1
Simple helper to consolidate biolerplate code. Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Amir Goldstein <[email protected]> Signed-off-by: Jan Kara <[email protected]>
2020-07-25bpf: Separate bpf_get_[stack|stackid] for perf events BPFSong Liu1-2/+2
Calling get_perf_callchain() on perf_events from PEBS entries may cause unwinder errors. To fix this issue, the callchain is fetched early. Such perf_events are marked with __PERF_SAMPLE_CALLCHAIN_EARLY. Similarly, calling bpf_get_[stack|stackid] on perf_events from PEBS may also cause unwinder errors. To fix this, add separate version of these two helpers, bpf_get_[stack|stackid]_pe. These two hepers use callchain in bpf_perf_event_data_kern->data->callchain. Signed-off-by: Song Liu <[email protected]> Signed-off-by: Alexei Starovoitov <[email protected]> Link: https://lore.kernel.org/bpf/[email protected]
2020-07-23tracefs: Remove unnecessary debug_fs checks.Peter Enderborg1-3/+1
This is a preparation for debugfs restricted mode. We don't need debugfs to trace, the removed check stop tracefs to work if debugfs is not initialised. We instead tries to automount within debugfs and relay on it's handling. The code path is to create a backward compatibility from when tracefs was part of debugfs, it is now standalone and does not need debugfs. When debugfs is in restricted it is compiled in but not active and return EPERM to clients and tracefs wont work if it assumes it is active it is compiled in kernel. Reported-by: kernel test robot <[email protected]> Signed-off-by: Peter Enderborg <[email protected]> Reviewed-by: Greg Kroah-Hartman <[email protected]> Acked-by: Steven Rostedt (VMware) <[email protected]> Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Greg Kroah-Hartman <[email protected]>
2020-07-16treewide: Remove uninitialized_var() usageKees Cook1-1/+1
Using uninitialized_var() is dangerous as it papers over real bugs[1] (or can in the future), and suppresses unrelated compiler warnings (e.g. "unused variable"). If the compiler thinks it is uninitialized, either simply initialize the variable or make compiler changes. In preparation for removing[2] the[3] macro[4], remove all remaining needless uses with the following script: git grep '\buninitialized_var\b' | cut -d: -f1 | sort -u | \ xargs perl -pi -e \ 's/\buninitialized_var\(([^\)]+)\)/\1/g; s:\s*/\* (GCC be quiet|to make compiler happy) \*/$::g;' drivers/video/fbdev/riva/riva_hw.c was manually tweaked to avoid pathological white-space. No outstanding warnings were found building allmodconfig with GCC 9.3.0 for x86_64, i386, arm64, arm, powerpc, powerpc64le, s390x, mips, sparc64, alpha, and m68k. [1] https://lore.kernel.org/lkml/[email protected]/ [2] https://lore.kernel.org/lkml/CA+55aFw+Vbj0i=1TGqCR5vQkCzWJ0QxK6CernOU6eedsudAixw@mail.gmail.com/ [3] https://lore.kernel.org/lkml/CA+55aFwgbgqhbp1fkxvRKEpzyR5J8n1vKT1VZdz9knmPuXhOeg@mail.gmail.com/ [4] https://lore.kernel.org/lkml/CA+55aFz2500WfbKXAx8s67wrm9=yVJu65TpLgN_ybYNv0VEOKA@mail.gmail.com/ Reviewed-by: Leon Romanovsky <[email protected]> # drivers/infiniband and mlx4/mlx5 Acked-by: Jason Gunthorpe <[email protected]> # IB Acked-by: Kalle Valo <[email protected]> # wireless drivers Reviewed-by: Chao Yu <[email protected]> # erofs Signed-off-by: Kees Cook <[email protected]>
2020-07-13bpf: Use dedicated bpf_trace_printk event instead of trace_printk()Alan Maguire3-5/+73
The bpf helper bpf_trace_printk() uses trace_printk() under the hood. This leads to an alarming warning message originating from trace buffer allocation which occurs the first time a program using bpf_trace_printk() is loaded. We can instead create a trace event for bpf_trace_printk() and enable it in-kernel when/if we encounter a program using the bpf_trace_printk() helper. With this approach, trace_printk() is not used directly and no warning message appears. This work was started by Steven (see Link) and finished by Alan; added Steven's Signed-off-by with his permission. Signed-off-by: Steven Rostedt (VMware) <[email protected]> Signed-off-by: Alan Maguire <[email protected]> Signed-off-by: Alexei Starovoitov <[email protected]> Acked-by: Andrii Nakryiko <[email protected]> Link: https://lore.kernel.org/r/[email protected] Link: https://lore.kernel.org/bpf/[email protected]
2020-07-13bpf: Resolve BTF IDs in vmlinux imageJiri Olsa1-2/+7
Using BTF_ID_LIST macro to define lists for several helpers using BTF arguments. And running resolve_btfids on vmlinux elf object during linking, so the .BTF_ids section gets the IDs resolved. Signed-off-by: Jiri Olsa <[email protected]> Signed-off-by: Alexei Starovoitov <[email protected]> Tested-by: Andrii Nakryiko <[email protected]> Acked-by: Andrii Nakryiko <[email protected]> Link: https://lore.kernel.org/bpf/[email protected]
2020-07-09tracing: Save one trace_event->type by using __TRACE_LAST_TYPEWei Yang1-2/+2
Static defined trace_event->type stops at (__TRACE_LAST_TYPE - 1) and dynamic trace_event->type starts from (__TRACE_LAST_TYPE + 1). To save one trace_event->type index, let's use __TRACE_LAST_TYPE. Link: https://lkml.kernel.org/r/[email protected] Signed-off-by: Wei Yang <[email protected]> Signed-off-by: Steven Rostedt (VMware) <[email protected]>
2020-07-09tracing: Simplify defining of the next event idWei Yang1-6/+6
The value to be used and compared in trace_search_list() is "last + 1". Let's just define next to be "last + 1" instead of doing the addition each time. Link: https://lkml.kernel.org/r/[email protected] Signed-off-by: Wei Yang <[email protected]> Signed-off-by: Steven Rostedt (VMware) <[email protected]>
2020-07-04Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-nextDavid S. Miller1-3/+24
Daniel Borkmann says: ==================== pull-request: bpf-next 2020-07-04 The following pull-request contains BPF updates for your *net-next* tree. We've added 73 non-merge commits during the last 17 day(s) which contain a total of 106 files changed, 5233 insertions(+), 1283 deletions(-). The main changes are: 1) bpftool ability to show PIDs of processes having open file descriptors for BPF map/program/link/BTF objects, relying on BPF iterator progs to extract this info efficiently, from Andrii Nakryiko. 2) Addition of BPF iterator progs for dumping TCP and UDP sockets to seq_files, from Yonghong Song. 3) Support access to BPF map fields in struct bpf_map from programs through BTF struct access, from Andrey Ignatov. 4) Add a bpf_get_task_stack() helper to be able to dump /proc/*/stack via seq_file from BPF iterator progs, from Song Liu. 5) Make SO_KEEPALIVE and related options available to bpf_setsockopt() helper, from Dmitry Yakunin. 6) Optimize BPF sk_storage selection of its caching index, from Martin KaFai Lau. 7) Removal of redundant synchronize_rcu()s from BPF map destruction which has been a historic leftover, from Alexei Starovoitov. 8) Several improvements to test_progs to make it easier to create a shell loop that invokes each test individually which is useful for some CIs, from Jesper Dangaard Brouer. 9) Fix bpftool prog dump segfault when compiled without skeleton code on older clang versions, from John Fastabend. 10) Bunch of cleanups and minor improvements, from various others. ==================== Signed-off-by: David S. Miller <[email protected]>
2020-07-02Merge branch 'perf/vlbr'Peter Zijlstra14-39/+96
2020-07-01ring-buffer: Do not trigger a WARN if clock going backwards is detectedSteven Rostedt (VMware)1-3/+21
After tweaking the ring buffer to be a bit faster, a warning is triggering on one of my machines, and causing my tests to fail. This warning is caused when the delta (current time stamp minus previous time stamp), is larger than the max time held by the ring buffer (59 bits). If the clock were to go backwards slightly, this would then easily trigger this warning. The machine that it triggered on, the clock did go backwards by around 450 nanoseconds, and this happened after a recalibration of the TSC clock. Now that the ring buffer is faster, it detects this, and the delta that is used larger than the max, the warning is triggered and my test fails. To handle the clock going backwards, look at the saved before and after time stamps. If they are the same, it means that the current event did not interrupt another event, and that those timestamp are of a previous event that was recorded. If the max delta is triggered, look at those time stamps, make sure they are the same, then use them to compare with the current timestamp. If the current timestamp is less than the before/after time stamps, then that means the clock being used went backward. Print out a message that this has happened, but do not warn about it (and only print the message once). Still do the warning if the delta is indeed larger than what can be used. Also remove the unneeded KERN_WARNING from the WARN_ONCE() print. Signed-off-by: Steven Rostedt (VMware) <[email protected]>
2020-07-01ring-buffer: Call trace_clock_local() directly for RETPOLINE kernelsSteven Rostedt (VMware)1-1/+9
After doing some benchmarks and examining the code, I found that the ring buffer clock calls were quite expensive, and noticed that it uses retpolines. This is because the ring buffer clock is programmable, and can be set. But in most cases it simply uses the fastest ns unit clock which is the trace_clock_local(). For RETPOLINE builds, checking if the ring buffer clock is set to trace_clock_local() and then calling it directly has brought the time of an event on my i7 box from an average of 93 nanoseconds an event down to 83 nanoseconds an event, and the minimum time from 81 nanoseconds to 68 nanoseconds! Suggested-by: Mathieu Desnoyers <[email protected]> Signed-off-by: Steven Rostedt (VMware) <[email protected]>
2020-07-01ring-buffer: Move the add_timestamp into its own functionSteven Rostedt (VMware)1-12/+20
Make a helper function rb_add_timestamp() that moves the adding of the extended time stamps into its own function. Also, remove the noinline and inline for the functions it calls, as recent benchmarks appear they do not make a difference (just let gcc decide). Signed-off-by: Steven Rostedt (VMware) <[email protected]>
2020-07-01ring-buffer: Consolidate add_timestamp to remove some branchesSteven Rostedt (VMware)1-66/+73
Reorganize a little the logic to handle adding the absolute time stamp, extended and forced time stamps, in such a way to remove a branch or two. This is just a micro optimization. Also add before and after time stamps to the rb_event_info structure to display those values in the rb_check_timestamps() code, if something were to go wrong. Suggested-by: Mathieu Desnoyers <[email protected]> Signed-off-by: Steven Rostedt (VMware) <[email protected]>
2020-07-01bpf: Allow %pB in bpf_seq_printf() and bpf_trace_printk()Song Liu1-2/+8
This makes it easy to dump stack trace in text. Signed-off-by: Song Liu <[email protected]> Signed-off-by: Alexei Starovoitov <[email protected]> Acked-by: Yonghong Song <[email protected]> Acked-by: Andrii Nakryiko <[email protected]> Link: https://lore.kernel.org/bpf/[email protected]
2020-07-01bpf: Introduce helper bpf_get_task_stack()Song Liu1-0/+2
Introduce helper bpf_get_task_stack(), which dumps stack trace of given task. This is different to bpf_get_stack(), which gets stack track of current task. One potential use case of bpf_get_task_stack() is to call it from bpf_iter__task and dump all /proc/<pid>/stack to a seq_file. bpf_get_task_stack() uses stack_trace_save_tsk() instead of get_perf_callchain() for kernel stack. The benefit of this choice is that stack_trace_save_tsk() doesn't require changes in arch/. The downside of using stack_trace_save_tsk() is that stack_trace_save_tsk() dumps the stack trace to unsigned long array. For 32-bit systems, we need to translate it to u64 array. Signed-off-by: Song Liu <[email protected]> Signed-off-by: Alexei Starovoitov <[email protected]> Acked-by: Andrii Nakryiko <[email protected]> Link: https://lore.kernel.org/bpf/[email protected]
2020-06-30ring-buffer: Mark the !tail (crossing a page) as unlikelySteven Rostedt (VMware)1-1/+1
It is the uncommon case where an event crosses a sub buffer boundary (page) mark that check at the end of reserving an event as unlikely. Suggested-by: Mathieu Desnoyers <[email protected]> Signed-off-by: Steven Rostedt (VMware) <[email protected]>
2020-06-30ring-buffer: speed up buffer resets by avoiding synchronize_rcu for each CPUNicholas Piggin2-17/+72
On a 144 thread system, `perf ftrace` takes about 20 seconds to start up, due to calling synchronize_rcu() for each CPU. cat /proc/108560/stack 0xc0003e7eb336f470 __switch_to+0x2e0/0x480 __wait_rcu_gp+0x20c/0x220 synchronize_rcu+0x9c/0xc0 ring_buffer_reset_cpu+0x88/0x2e0 tracing_reset_online_cpus+0x84/0xe0 tracing_open+0x1d4/0x1f0 On a system with 10x more threads, it starts to become an annoyance. Batch these up so we disable all the per-cpu buffers first, then synchronize_rcu() once, then reset each of the buffers. This brings the time down to about 0.5s. Link: https://lkml.kernel.org/r/[email protected] Tested-by: Anton Blanchard <[email protected]> Acked-by: Paul E. McKenney <[email protected]> Signed-off-by: Nicholas Piggin <[email protected]> Signed-off-by: Steven Rostedt (VMware) <[email protected]>
2020-06-30ring-buffer: Add rb_time_t 64 bit operations for speeding up 32 bitSteven Rostedt (VMware)1-27/+243
After a discussion with the new time algorithm to have nested events still have proper time keeping but required using local64_t atomic operations. Mathieu was concerned about the performance this would have on 32 bit machines, as in most cases, atomic 64 bit operations on them can be expensive. As the ring buffer's timing needs do not require full features of local64_t, a wrapper is made to implement a new rb_time_t operation that uses two longs on 32 bit machines but still uses the local64_t operations on 64 bit machines. There's a switch that can be made in the file to force 64 bit to use the 32 bit version just for testing purposes. All reads do not need to succeed if a read happened while the stamp being read is in the process of being updated. The requirement is that all reads must succed that were done by an interrupting event (where this event was interrupted by another event that did the write). Or if the event itself did the write first. That is: rb_time_set(t, x) followed by rb_time_read(t) will always succeed (even if it gets interrupted by another event that writes to t. The result of the read will be either the previous set, or a set performed by an interrupting event. If the read is done by an event that interrupted another event that was in the process of setting the time stamp, and no other event came along to write to that time stamp, it will fail and the rb_time_read() will return that it failed (the value to read will be undefined). A set will always write to the time stamp and return with a valid time stamp, such that any read after it will be valid. A cmpxchg may fail if it interrupted an event that was in the process of updating the time stamp just like the reads do. Other than that, it will act like a normal cmpxchg. The way this works is that the rb_time_t is made of of three fields. A cnt, that gets updated atomically everyting a modification is made. A top that represents the most significant 30 bits of the time, and a bottom to represent the least significant 30 bits of the time. Notice, that the time values is only 60 bits long (where the ring buffer only uses 59 bits, which gives us 18 years of nanoseconds!). The top two bits of both the top and bottom is a 2 bit counter that gets set by the value of the least two significant bits of the cnt. A read of the top and the bottom where both the top and bottom have the same most significant top 2 bits, are considered a match and a valid 60 bit number can be created from it. If they do not match, then the number is considered invalid, and this must only happen if an event interrupted another event in the midst of updating the time stamp. This is only used for 32 bits machines as 64 bit machines can get better performance out of the local64_t. This has been tested heavily by forcing 64 bit to use this logic. Link: https://lore.kernel.org/r/[email protected] Link: http://lkml.kernel.org/r/[email protected] Inspired-by: Mathieu Desnoyers <[email protected]> Signed-off-by: Steven Rostedt (VMware) <[email protected]>
2020-06-30ring-buffer: Incorporate absolute timestamp into add_timestamp logicSteven Rostedt (VMware)1-18/+22
Instead of calling out the absolute test for each time to check if the ring buffer wants absolute time stamps for all its recording, incorporate it with the add_timestamp field and turn it into flags for faster processing between wanting a absolute tag and needing to force one. Link: http://lkml.kernel.org/r/[email protected] Signed-off-by: Steven Rostedt (VMware) <[email protected]>
2020-06-30ring-buffer: Have nested events still record running time stampSteven Rostedt (VMware)1-95/+181
Up until now, if an event is interrupted while it is recorded by an interrupt, and that interrupt records events, the time of those events will all be the same. This is because events only record the delta of the time since the previous event (or beginning of a page), and to handle updating the time keeping for that of nested events is extremely racy. After years of thinking about this and several failed attempts, I finally have a solution to solve this puzzle. The problem is that you need to atomically calculate the delta and then update the time stamp you made the delta from, as well as then record it into the buffer, all this while at any time an interrupt can come in and do the same thing. This is easy to solve with heavy weight atomics, but that would be detrimental to the performance of the ring buffer. The current state of affairs sacrificed the time deltas for nested events for performance. The reason for previous failed attempts at solving this puzzle was because I was trying to completely avoid slow atomic operations like cmpxchg. I final came to the conclusion to always avoid cmpxchg is not possible, which is why those previous attempts always failed. But it is possible to pick one path (the most common case) and avoid cmpxchg in that path, which is the "fast path". The most common case is that an event will not be interrupted and have other events added into it. An event can detect if it has interrupted another event, and for these cases we can make it the slow path and use the heavy operations like cmpxchg. One more player was added to the game that made this possible, and that is the "absolute timestamp" (by Tom Zanussi) that allows us to inject a full 59 bit time stamp. (Of course this breaks if a machine is running for more than 18 years without a reboot!). There's barrier() placements around for being paranoid, even when they are not needed because of other atomic functions near by. But those should not hurt, as if they are not needed, they basically become a nop. Note, this also makes the race window much smaller, which means there are less slow paths to slow down the performance. The basic idea is that there's two main paths taken. 1) Not being interrupted between time stamps and reserving buffer space. In this case, the time stamps taken are true to the location in the buffer. 2) Was interrupted by another path between taking time stamps and reserving buffer space. The objective is to know what the delta is from the last reserved location in the buffer. As it is possible to detect if an event is interrupting another event before reserving data, space is added to the length to be reserved to inject a full time stamp along with the event being reserved. When an event is not interrupted, the write stamp is always the time of the last event written to the buffer. In path 1, there's two sub paths we care about: a) The event did not interrupt another event. b) The event interrupted another event. In case a, as the write stamp was read and known to be correct, the delta between the current time stamp and the write stamp is the delta between the current event and the previously recorded event. In case b, extra space was reserved to just put the full time stamp into the buffer. Which is done, as stated, in this path the time stamp taken is known to match the location in the buffer. In path 2, there's also two sub paths we care about: a) The event was not interrupted by another event since it reserved space on the buffer and re-reading the write stamp. b) The event was interrupted by another event. In case a, the write stamp is that of the last event that interrupted this event between taking the time stamps and reserving. As no event came in after re-reading the write stamp, that event is known to be the time of the event directly before this event and the delta can be the new time stamp and the write stamp. In case b, one or more events came in between reserving the event and re-reading he write stamp. Since this event's buffer reservation is between other events at this path, there's no way to know what the delta is. But because an event interrupted this event after it started, its fine to just give a zero delta, and take the same time stamp as the events that happened within the event being recorded. Here's the implementation of the design of this solution: All this is per cpu, and only needs to worry about nested events (not parallel events). The players: write_tail: The index in the buffer where new events can be written to. It is incremented via local_add() to reserve space for a new event. before_stamp: A time stamp set by all events before reserving space. write_stamp: A time stamp updated by events after it has successfully reserved space. /* Save the current position of write */ [A] w = local_read(write_tail); barrier(); /* Read both before and write stamps before touching anything */ before = local_read(before_stamp); after = local_read(write_stamp); barrier(); /* * If before and after are the same, then this event is not * interrupting a time update. If it is, then reserve space for adding * a full time stamp (this can turn into a time extend which is * just an extended time delta but fill up the extra space). */ if (after != before) abs = true; ts = clock(); /* Now update the before_stamp (everyone does this!) */ [B] local_set(before_stamp, ts); /* Now reserve space on the buffer */ [C] write = local_add_return(len, write_tail); /* Set tail to be were this event's data is */ tail = write - len; if (w == tail) { /* Nothing interrupted this between A and C */ [D] local_set(write_stamp, ts); barrier(); [E] save_before = local_read(before_stamp); if (!abs) { /* This did not interrupt a time update */ delta = ts - after; } else { delta = ts; /* The full time stamp will be in use */ } if (ts != save_before) { /* slow path - Was interrupted between C and E */ /* The update to write_stamp could have overwritten the update to * it by the interrupting event, but before and after should be * the same for all completed top events */ after = local_read(write_stamp); if (save_before > after) local_cmpxchg(write_stamp, after, save_before); } } else { /* slow path - Interrupted between A and C */ after = local_read(write_stamp); temp_ts = clock(); barrier(); [F] if (write == local_read(write_tail) && after < temp_ts) { /* This was not interrupted since C and F * The last write_stamp is still valid for the previous event * in the buffer. */ delta = temp_ts - after; /* OK to keep this new time stamp */ ts = temp_ts; } else { /* Interrupted between C and F * Well, there's no use to try to know what the time stamp * is for the previous event. Just set delta to zero and * be the same time as that event that interrupted us before * the reservation of the buffer. */ delta = 0; } /* No need to use full timestamps here */ abs = 0; } Link: https://lkml.kernel.org/r/[email protected] Link: https://lore.kernel.org/r/[email protected] Link: http://lkml.kernel.org/r/[email protected] Reviewed-by: Masami Hiramatsu <[email protected]> Signed-off-by: Steven Rostedt (VMware) <[email protected]>
2020-06-30tracing: Move pipe reference to trace array instead of current_tracerSteven Rostedt (VMware)2-7/+7
If a process has the trace_pipe open on a trace_array, the current tracer for that trace array should not be changed. This was original enforced by a global lock, but when instances were introduced, it was moved to the current_trace. But this structure is shared by all instances, and a trace_pipe is for a single instance. There's no reason that a process that has trace_pipe open on one instance should prevent another instance from changing its current tracer. Move the reference counter to the trace_array instead. This is marked as "Fixes" but is more of a clean up than a true fix. Backport if you want, but its not critical. Fixes: cf6ab6d9143b1 ("tracing: Add ref count to tracer for when they are being read by pipe") Signed-off-by: Steven Rostedt (VMware) <[email protected]>
2020-06-29x86/ftrace: Only have the builtin ftrace_regs_caller call direct hooksSteven Rostedt (VMware)1-0/+8
If a direct hook is attached to a function that ftrace also has a function attached to it, then it is required that the ftrace_ops_list_func() is used to iterate over the registered ftrace callbacks. This will also include the direct ftrace_ops helper, that tells ftrace_regs_caller where to return to (the direct callback and not the function that called it). As this direct helper is only to handle the case of ftrace callbacks attached to the same function as the direct callback, the ftrace callback allocated trampolines (used to only call them), should never be used to return back to a direct callback. Only copy the portion of the ftrace_regs_caller that will return back to what called it, and not the portion that returns back to the direct caller. The direct ftrace_ops must then pick the ftrace_regs_caller builtin function as its own trampoline to ensure that it will never have one allocated for it (which would not include the handling of direct callbacks). Link: http://lkml.kernel.org/r/[email protected] Cc: Peter Zijlstra <[email protected]> Signed-off-by: Steven Rostedt (VMware) <[email protected]>
2020-06-29tracing: Only allow trace_array_printk() to be used by instancesSteven Rostedt (VMware)1-3/+7
To prevent default "trace_printks()" from spamming the top level tracing ring buffer, only allow trace instances to use trace_array_printk() (which can be used without the trace_printk() start up warning). Signed-off-by: Steven Rostedt (VMware) <[email protected]>
2020-06-25blktrace: Provide event for request mergingJan Kara1-0/+10
Currently blk-mq does not report any event when two requests get merged in the elevator. This then results in difficult to understand sequence of events like: ... 8,0 34 1579 0.608765271 2718 I WS 215023504 + 40 [dbench] 8,0 34 1584 0.609184613 2719 A WS 215023544 + 56 <- (8,4) 2160568 8,0 34 1585 0.609184850 2719 Q WS 215023544 + 56 [dbench] 8,0 34 1586 0.609188524 2719 G WS 215023544 + 56 [dbench] 8,0 3 602 0.609684162 773 D WS 215023504 + 96 [kworker/3:1H] 8,0 34 1591 0.609843593 0 C WS 215023504 + 96 [0] and you can only guess (after quite some headscratching since the above excerpt is intermixed with a lot of other IO) that request 215023544+56 got merged to request 215023504+40. Provide proper event for request merging like we used to do in the legacy block layer. Signed-off-by: Jan Kara <[email protected]> Signed-off-by: Jens Axboe <[email protected]>
2020-06-25Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/netLinus Torvalds1-1/+1
Pull networking fixes from David Miller: 1) Don't insert ESP trailer twice in IPSEC code, from Huy Nguyen. 2) The default crypto algorithm selection in Kconfig for IPSEC is out of touch with modern reality, fix this up. From Eric Biggers. 3) bpftool is missing an entry for BPF_MAP_TYPE_RINGBUF, from Andrii Nakryiko. 4) Missing init of ->frame_sz in xdp_convert_zc_to_xdp_frame(), from Hangbin Liu. 5) Adjust packet alignment handling in ax88179_178a driver to match what the hardware actually does. From Jeremy Kerr. 6) register_netdevice can leak in the case one of the notifiers fail, from Yang Yingliang. 7) Use after free in ip_tunnel_lookup(), from Taehee Yoo. 8) VLAN checks in sja1105 DSA driver need adjustments, from Vladimir Oltean. 9) tg3 driver can sleep forever when we get enough EEH errors, fix from David Christensen. 10) Missing {READ,WRITE}_ONCE() annotations in various Intel ethernet drivers, from Ciara Loftus. 11) Fix scanning loop break condition in of_mdiobus_register(), from Florian Fainelli. 12) MTU limit is incorrect in ibmveth driver, from Thomas Falcon. 13) Endianness fix in mlxsw, from Ido Schimmel. 14) Use after free in smsc95xx usbnet driver, from Tuomas Tynkkynen. 15) Missing bridge mrp configuration validation, from Horatiu Vultur. 16) Fix circular netns references in wireguard, from Jason A. Donenfeld. 17) PTP initialization on recovery is not done properly in qed driver, from Alexander Lobakin. 18) Endian conversion of L4 ports in filters of cxgb4 driver is wrong, from Rahul Lakkireddy. 19) Don't clear bound device TX queue of socket prematurely otherwise we get problems with ktls hw offloading, from Tariq Toukan. 20) ipset can do atomics on unaligned memory, fix from Russell King. 21) Align ethernet addresses properly in bridging code, from Thomas Martitz. 22) Don't advertise ipv4 addresses on SCTP sockets having ipv6only set, from Marcelo Ricardo Leitner. * git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net: (149 commits) rds: transport module should be auto loaded when transport is set sch_cake: fix a few style nits sch_cake: don't call diffserv parsing code when it is not needed sch_cake: don't try to reallocate or unshare skb unconditionally ethtool: fix error handling in linkstate_prepare_data() wil6210: account for napi_gro_receive never returning GRO_DROP hns: do not cast return value of napi_gro_receive to null socionext: account for napi_gro_receive never returning GRO_DROP wireguard: receive: account for napi_gro_receive never returning GRO_DROP vxlan: fix last fdb index during dump of fdb with nhid sctp: Don't advertise IPv4 addresses if ipv6only is set on the socket tc-testing: avoid action cookies with odd length. bpf: tcp: bpf_cubic: fix spurious HYSTART_DELAY exit upon drop in min RTT tcp_cubic: fix spurious HYSTART_DELAY exit upon drop in min RTT net: dsa: sja1105: fix tc-gate schedule with single element net: dsa: sja1105: recalculate gating subschedule after deleting tc-gate rules net: dsa: sja1105: unconditionally free old gating config net: dsa: sja1105: move sja1105_compose_gating_subschedule at the top net: macb: free resources on failure path of at91ether_open() net: macb: call pm_runtime_put_sync on failure path ...
2020-06-24bpf: Add bpf_skc_to_udp6_sock() helperYonghong Song1-0/+2
The helper is used in tracing programs to cast a socket pointer to a udp6_sock pointer. The return value could be NULL if the casting is illegal. Signed-off-by: Yonghong Song <[email protected]> Signed-off-by: Alexei Starovoitov <[email protected]> Acked-by: Martin KaFai Lau <[email protected]> Cc: Eric Dumazet <[email protected]> Link: https://lore.kernel.org/bpf/[email protected]
2020-06-24bpf: Add bpf_skc_to_{tcp, tcp_timewait, tcp_request}_sock() helpersYonghong Song1-0/+6
Three more helpers are added to cast a sock_common pointer to an tcp_sock, tcp_timewait_sock or a tcp_request_sock for tracing programs. Signed-off-by: Yonghong Song <[email protected]> Signed-off-by: Alexei Starovoitov <[email protected]> Acked-by: Martin KaFai Lau <[email protected]> Link: https://lore.kernel.org/bpf/[email protected]
2020-06-24bpf: Add bpf_skc_to_tcp6_sock() helperYonghong Song1-0/+2
The helper is used in tracing programs to cast a socket pointer to a tcp6_sock pointer. The return value could be NULL if the casting is illegal. A new helper return type RET_PTR_TO_BTF_ID_OR_NULL is added so the verifier is able to deduce proper return types for the helper. Different from the previous BTF_ID based helpers, the bpf_skc_to_tcp6_sock() argument can be several possible btf_ids. More specifically, all possible socket data structures with sock_common appearing in the first in the memory layout. This patch only added socket types related to tcp and udp. All possible argument btf_id and return value btf_id for helper bpf_skc_to_tcp6_sock() are pre-calculcated and cached. In the future, it is even possible to precompute these btf_id's at kernel build time. Signed-off-by: Yonghong Song <[email protected]> Signed-off-by: Alexei Starovoitov <[email protected]> Acked-by: Andrii Nakryiko <[email protected]> Acked-by: Martin KaFai Lau <[email protected]> Link: https://lore.kernel.org/bpf/[email protected]
2020-06-24bpf: Allow tracing programs to use bpf_jiffies64() helperYonghong Song1-0/+2
/proc/net/tcp{4,6} uses jiffies for various computations. Let us add bpf_jiffies64() helper to tracing program so bpf_iter and other programs can use it. Signed-off-by: Yonghong Song <[email protected]> Signed-off-by: Alexei Starovoitov <[email protected]> Acked-by: Martin KaFai Lau <[email protected]> Link: https://lore.kernel.org/bpf/[email protected]
2020-06-24bpf: Support 'X' in bpf_seq_printf() helperYonghong Song1-1/+2
'X' tells kernel to print hex with upper case letters. /proc/net/tcp{4,6} seq_file show() used this, and supports it in bpf_seq_printf() helper too. Signed-off-by: Yonghong Song <[email protected]> Signed-off-by: Alexei Starovoitov <[email protected]> Acked-by: Martin KaFai Lau <[email protected]> Link: https://lore.kernel.org/bpf/[email protected]
2020-06-24block: create the request_queue debugfs_dir on registrationLuis Chamberlain1-32/+26
We were only creating the request_queue debugfs_dir only for make_request block drivers (multiqueue), but never for request-based block drivers. We did this as we were only creating non-blktrace additional debugfs files on that directory for make_request drivers. However, since blktrace *always* creates that directory anyway, we special-case the use of that directory on blktrace. Other than this being an eye-sore, this exposes request-based block drivers to the same debugfs fragile race that used to exist with make_request block drivers where if we start adding files onto that directory we can later run a race with a double removal of dentries on the directory if we don't deal with this carefully on blktrace. Instead, just simplify things by always creating the request_queue debugfs_dir on request_queue registration. Rename the mutex also to reflect the fact that this is used outside of the blktrace context. Signed-off-by: Luis Chamberlain <[email protected]> Reviewed-by: Christoph Hellwig <[email protected]> Signed-off-by: Jens Axboe <[email protected]>
2020-06-24blktrace: ensure our debugfs dir existsLuis Chamberlain1-0/+12
We make an assumption that a debugfs directory exists, but since this can fail ensure it exists before allowing blktrace setup to complete. Otherwise we end up stuffing blktrace files on the debugfs root directory. In the worst case scenario this *in theory* can create an eventual panic *iff* in the future a similarly named file is created prior on the debugfs root directory. This theoretical crash can happen due to a recursive removal followed by a specific dentry removal. This doesn't fix any known crash, however I have seen the files go into the main debugfs root directory in cases where the debugfs directory was not created due to other internal bugs with blktrace now fixed. blktrace is also completely useless without this directory, so this ensures to userspace we only setup blktrace if the kernel can stuff files where they are supposed to go into. debugfs directory creations typically aren't checked for, and we have maintainers doing sweep removals of these checks, but since we need this check to ensure proper userspace blktrace functionality we make sure to annotate the justification for the check. Signed-off-by: Luis Chamberlain <[email protected]> Reviewed-by: Christoph Hellwig <[email protected]> Reviewed-by: Bart Van Assche <[email protected]> Signed-off-by: Jens Axboe <[email protected]>
2020-06-24blktrace: fix debugfs use after freeLuis Chamberlain1-6/+12
On commit 6ac93117ab00 ("blktrace: use existing disk debugfs directory") merged on v4.12 Omar fixed the original blktrace code for request-based drivers (multiqueue). This however left in place a possible crash, if you happen to abuse blktrace while racing to remove / add a device. We used to use asynchronous removal of the request_queue, and with that the issue was easier to reproduce. Now that we have reverted to synchronous removal of the request_queue, the issue is still possible to reproduce, its however just a bit more difficult. We essentially run two instances of break-blktrace which add/remove a loop device, and setup a blktrace and just never tear the blktrace down. We do this twice in parallel. This is easily reproduced with the script run_0004.sh from break-blktrace [0]. We can end up with two types of panics each reflecting where we race, one a failed blktrace setup: [ 252.426751] debugfs: Directory 'loop0' with parent 'block' already present! [ 252.432265] BUG: kernel NULL pointer dereference, address: 00000000000000a0 [ 252.436592] #PF: supervisor write access in kernel mode [ 252.439822] #PF: error_code(0x0002) - not-present page [ 252.442967] PGD 0 P4D 0 [ 252.444656] Oops: 0002 [#1] SMP NOPTI [ 252.446972] CPU: 10 PID: 1153 Comm: break-blktrace Tainted: G E 5.7.0-rc2-next-20200420+ #164 [ 252.452673] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-1 04/01/2014 [ 252.456343] RIP: 0010:down_write+0x15/0x40 [ 252.458146] Code: eb ca e8 ae 22 8d ff cc cc cc cc cc cc cc cc cc cc cc cc cc cc 0f 1f 44 00 00 55 48 89 fd e8 52 db ff ff 31 c0 ba 01 00 00 00 <f0> 48 0f b1 55 00 75 0f 48 8b 04 25 c0 8b 01 00 48 89 45 08 5d [ 252.463638] RSP: 0018:ffffa626415abcc8 EFLAGS: 00010246 [ 252.464950] RAX: 0000000000000000 RBX: ffff958c25f0f5c0 RCX: ffffff8100000000 [ 252.466727] RDX: 0000000000000001 RSI: ffffff8100000000 RDI: 00000000000000a0 [ 252.468482] RBP: 00000000000000a0 R08: 0000000000000000 R09: 0000000000000001 [ 252.470014] R10: 0000000000000000 R11: ffff958d1f9227ff R12: 0000000000000000 [ 252.471473] R13: ffff958c25ea5380 R14: ffffffff8cce15f1 R15: 00000000000000a0 [ 252.473346] FS: 00007f2e69dee540(0000) GS:ffff958c2fc80000(0000) knlGS:0000000000000000 [ 252.475225] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 252.476267] CR2: 00000000000000a0 CR3: 0000000427d10004 CR4: 0000000000360ee0 [ 252.477526] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 252.478776] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 252.479866] Call Trace: [ 252.480322] simple_recursive_removal+0x4e/0x2e0 [ 252.481078] ? debugfs_remove+0x60/0x60 [ 252.481725] ? relay_destroy_buf+0x77/0xb0 [ 252.482662] debugfs_remove+0x40/0x60 [ 252.483518] blk_remove_buf_file_callback+0x5/0x10 [ 252.484328] relay_close_buf+0x2e/0x60 [ 252.484930] relay_open+0x1ce/0x2c0 [ 252.485520] do_blk_trace_setup+0x14f/0x2b0 [ 252.486187] __blk_trace_setup+0x54/0xb0 [ 252.486803] blk_trace_ioctl+0x90/0x140 [ 252.487423] ? do_sys_openat2+0x1ab/0x2d0 [ 252.488053] blkdev_ioctl+0x4d/0x260 [ 252.488636] block_ioctl+0x39/0x40 [ 252.489139] ksys_ioctl+0x87/0xc0 [ 252.489675] __x64_sys_ioctl+0x16/0x20 [ 252.490380] do_syscall_64+0x52/0x180 [ 252.491032] entry_SYSCALL_64_after_hwframe+0x44/0xa9 And the other on the device removal: [ 128.528940] debugfs: Directory 'loop0' with parent 'block' already present! [ 128.615325] BUG: kernel NULL pointer dereference, address: 00000000000000a0 [ 128.619537] #PF: supervisor write access in kernel mode [ 128.622700] #PF: error_code(0x0002) - not-present page [ 128.625842] PGD 0 P4D 0 [ 128.627585] Oops: 0002 [#1] SMP NOPTI [ 128.629871] CPU: 12 PID: 544 Comm: break-blktrace Tainted: G E 5.7.0-rc2-next-20200420+ #164 [ 128.635595] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-1 04/01/2014 [ 128.640471] RIP: 0010:down_write+0x15/0x40 [ 128.643041] Code: eb ca e8 ae 22 8d ff cc cc cc cc cc cc cc cc cc cc cc cc cc cc 0f 1f 44 00 00 55 48 89 fd e8 52 db ff ff 31 c0 ba 01 00 00 00 <f0> 48 0f b1 55 00 75 0f 65 48 8b 04 25 c0 8b 01 00 48 89 45 08 5d [ 128.650180] RSP: 0018:ffffa9c3c05ebd78 EFLAGS: 00010246 [ 128.651820] RAX: 0000000000000000 RBX: ffff8ae9a6370240 RCX: ffffff8100000000 [ 128.653942] RDX: 0000000000000001 RSI: ffffff8100000000 RDI: 00000000000000a0 [ 128.655720] RBP: 00000000000000a0 R08: 0000000000000002 R09: ffff8ae9afd2d3d0 [ 128.657400] R10: 0000000000000056 R11: 0000000000000000 R12: 0000000000000000 [ 128.659099] R13: 0000000000000000 R14: 0000000000000003 R15: 00000000000000a0 [ 128.660500] FS: 00007febfd995540(0000) GS:ffff8ae9afd00000(0000) knlGS:0000000000000000 [ 128.662204] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 128.663426] CR2: 00000000000000a0 CR3: 0000000420042003 CR4: 0000000000360ee0 [ 128.664776] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 128.666022] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 128.667282] Call Trace: [ 128.667801] simple_recursive_removal+0x4e/0x2e0 [ 128.668663] ? debugfs_remove+0x60/0x60 [ 128.669368] debugfs_remove+0x40/0x60 [ 128.669985] blk_trace_free+0xd/0x50 [ 128.670593] __blk_trace_remove+0x27/0x40 [ 128.671274] blk_trace_shutdown+0x30/0x40 [ 128.671935] blk_release_queue+0x95/0xf0 [ 128.672589] kobject_put+0xa5/0x1b0 [ 128.673188] disk_release+0xa2/0xc0 [ 128.673786] device_release+0x28/0x80 [ 128.674376] kobject_put+0xa5/0x1b0 [ 128.674915] loop_remove+0x39/0x50 [loop] [ 128.675511] loop_control_ioctl+0x113/0x130 [loop] [ 128.676199] ksys_ioctl+0x87/0xc0 [ 128.676708] __x64_sys_ioctl+0x16/0x20 [ 128.677274] do_syscall_64+0x52/0x180 [ 128.677823] entry_SYSCALL_64_after_hwframe+0x44/0xa9 The common theme here is: debugfs: Directory 'loop0' with parent 'block' already present This crash happens because of how blktrace uses the debugfs directory where it places its files. Upon init we always create the same directory which would be needed by blktrace but we only do this for make_request drivers (multiqueue) block drivers. When you race a removal of these devices with a blktrace setup you end up in a situation where the make_request recursive debugfs removal will sweep away the blktrace files and then later blktrace will also try to remove individual dentries which are already NULL. The inverse is also possible and hence the two types of use after frees. We don't create the block debugfs directory on init for these types of block devices: * request-based block driver block devices * every possible partition * scsi-generic And so, this race should in theory only be possible with make_request drivers. We can fix the UAF by simply re-using the debugfs directory for make_request drivers (multiqueue) and only creating the ephemeral directory for the other type of block devices. The new clarifications on relying on the q->blk_trace_mutex *and* also checking for q->blk_trace *prior* to processing a blktrace ensures the debugfs directories are only created if no possible directory name clashes are possible. This goes tested with: o nvme partitions o ISCSI with tgt, and blktracing against scsi-generic with: o block o tape o cdrom o media changer o blktests This patch is part of the work which disputes the severity of CVE-2019-19770 which shows this issue is not a core debugfs issue, but a misuse of debugfs within blktace. Fixes: 6ac93117ab00 ("blktrace: use existing disk debugfs directory") Reported-by: [email protected] Signed-off-by: Luis Chamberlain <[email protected]> Reviewed-by: Christoph Hellwig <[email protected]> Cc: Bart Van Assche <[email protected]> Cc: Omar Sandoval <[email protected]> Cc: Hannes Reinecke <[email protected]> Cc: Nicolai Stange <[email protected]> Cc: Greg Kroah-Hartman <[email protected]> Cc: Michal Hocko <[email protected]> Cc: "Martin K. Petersen" <[email protected]> Cc: "James E.J. Bottomley" <[email protected]> Cc: yu kuai <[email protected]> Signed-off-by: Jens Axboe <[email protected]>
2020-06-24blktrace: annotate required lock on do_blk_trace_setup()Luis Chamberlain1-0/+2
Ensure it is clear which lock is required on do_blk_trace_setup(). Suggested-by: Bart Van Assche <[email protected]> Signed-off-by: Luis Chamberlain <[email protected]> Reviewed-by: Bart Van Assche <[email protected]> Signed-off-by: Jens Axboe <[email protected]>
2020-06-23tracing/boottime: Fix kprobe multiple eventsSascha Ortmann1-2/+6
Fix boottime kprobe events to report and abort after each failure when adding probes. As an example, when we try to set multiprobe kprobe events in bootconfig like this: ftrace.event.kprobes.vfsevents { probes = "vfs_read $arg1 $arg2,, !error! not reported;?", // leads to error "vfs_write $arg1 $arg2" } This will not work as expected. After commit da0f1f4167e3af69e ("tracing/boottime: Fix kprobe event API usage"), the function trace_boot_add_kprobe_event will not produce any error message when adding a probe fails at kprobe_event_gen_cmd_start. Furthermore, we continue to add probes when kprobe_event_gen_cmd_end fails (and kprobe_event_gen_cmd_start did not fail). In this case the function even returns successfully when the last call to kprobe_event_gen_cmd_end is successful. The behaviour of reporting and aborting after failures is not consistent. The function trace_boot_add_kprobe_event now reports each failure and stops adding probes immediately. Link: https://lkml.kernel.org/r/[email protected] Cc: [email protected] Cc: [email protected] Co-developed-by: Maximilian Werner <[email protected]> Fixes: da0f1f4167e3 ("tracing/boottime: Fix kprobe event API usage") Acked-by: Masami Hiramatsu <[email protected]> Signed-off-by: Maximilian Werner <[email protected]> Signed-off-by: Sascha Ortmann <[email protected]> Signed-off-by: Steven Rostedt (VMware) <[email protected]>
2020-06-23tracing: Fix event trigger to accept redundant spacesMasami Hiramatsu1-2/+19
Fix the event trigger to accept redundant spaces in the trigger input. For example, these return -EINVAL echo " traceon" > events/ftrace/print/trigger echo "traceon if common_pid == 0" > events/ftrace/print/trigger echo "disable_event:kmem:kmalloc " > events/ftrace/print/trigger But these are hard to find what is wrong. To fix this issue, use skip_spaces() to remove spaces in front of actual tokens, and set NULL if there is no token. Link: http://lkml.kernel.org/r/159262476352.185015.5261566783045364186.stgit@devnote2 Cc: Tom Zanussi <[email protected]> Cc: [email protected] Fixes: 85f2b08268c0 ("tracing: Add basic event trigger framework") Reviewed-by: Tom Zanussi <[email protected]> Signed-off-by: Masami Hiramatsu <[email protected]> Signed-off-by: Steven Rostedt (VMware) <[email protected]>
2020-06-23tracing/boot: Fix config dependency for synthedic eventMasami Hiramatsu1-1/+1
Since commit 726721a51838 ("tracing: Move synthetic events to a separate file") decoupled synthetic event from histogram, boot-time tracing also has to check CONFIG_SYNTH_EVENT instead of CONFIG_HIST_TRIGGERS. Link: http://lkml.kernel.org/r/159262475441.185015.5300725180746017555.stgit@devnote2 Fixes: 726721a51838 ("tracing: Move synthetic events to a separate file") Reviewed-by: Tom Zanussi <[email protected]> Signed-off-by: Masami Hiramatsu <[email protected]> Signed-off-by: Steven Rostedt (VMware) <[email protected]>
2020-06-23Merge up to bpf_probe_read_kernel_str() fix into bpf-nextAlexei Starovoitov1-1/+1
2020-06-23ring-buffer: Zero out time extend if it is nested and not absoluteSteven Rostedt (VMware)1-1/+1
Currently the ring buffer makes events that happen in interrupts that preempt another event have a delta of zero. (Hopefully we can change this soon). But this is to deal with the races of updating a global counter with lockless and nesting functions updating deltas. With the addition of absolute time stamps, the time extend didn't follow this rule. A time extend can happen if two events happen longer than 2^27 nanoseconds appart, as the delta time field in each event is only 27 bits. If that happens, then a time extend is injected with 2^59 bits of nanoseconds to use (18 years). But if the 2^27 nanoseconds happen between two events, and as it is writing the event, an interrupt triggers, it will see the 2^27 difference as well and inject a time extend of its own. But a recent change made the time extend logic not take into account the nesting, and this can cause two time extend deltas to happen moving the time stamp much further ahead than the current time. This gets all reset when the ring buffer moves to the next page, but that can cause time to appear to go backwards. This was observed in a trace-cmd recording, and since the data is saved in a file, with trace-cmd report --debug, it was possible to see that this indeed did happen! bash-52501 110d... 81778.908247: sched_switch: bash:52501 [120] S ==> swapper/110:0 [120] [12770284:0x2e8:64] <idle>-0 110d... 81778.908757: sched_switch: swapper/110:0 [120] R ==> bash:52501 [120] [509947:0x32c:64] TIME EXTEND: delta:306454770 length:0 bash-52501 110.... 81779.215212: sched_swap_numa: src_pid=52501 src_tgid=52388 src_ngid=52501 src_cpu=110 src_nid=2 dst_pid=52509 dst_tgid=52388 dst_ngid=52501 dst_cpu=49 dst_nid=1 [0:0x378:48] TIME EXTEND: delta:306458165 length:0 bash-52501 110dNh. 81779.521670: sched_wakeup: migration/110:565 [0] success=1 CPU:110 [0:0x3b4:40] and at the next page, caused the time to go backwards: bash-52504 110d... 81779.685411: sched_switch: bash:52504 [120] S ==> swapper/110:0 [120] [8347057:0xfb4:64] CPU:110 [SUBBUFFER START] [81779379165886:0x1320000] <idle>-0 110dN.. 81779.379166: sched_wakeup: bash:52504 [120] success=1 CPU:110 [0:0x10:40] <idle>-0 110d... 81779.379167: sched_switch: swapper/110:0 [120] R ==> bash:52504 [120] [1168:0x3c:64] Link: https://lkml.kernel.org/r/[email protected] Cc: Ingo Molnar <[email protected]> Cc: Andrew Morton <[email protected]> Cc: Tom Zanussi <[email protected]> Cc: [email protected] Fixes: dc4e2801d400b ("ring-buffer: Redefine the unimplemented RINGBUF_TYPE_TIME_STAMP") Reported-by: Julia Lawall <[email protected]> Signed-off-by: Steven Rostedt (VMware) <[email protected]>
2020-06-20Merge tag 'trace-v5.8-rc1' of ↵Linus Torvalds7-14/+40
git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace Pull tracing fixes from Steven Rostedt: - Have recordmcount work with > 64K sections (to support LTO) - kprobe RCU fixes - Correct a kprobe critical section with missing mutex - Remove redundant arch_disarm_kprobe() call - Fix lockup when kretprobe triggers within kprobe_flush_task() - Fix memory leak in fetch_op_data operations - Fix sleep in atomic in ftrace trace array sample code - Free up memory on failure in sample trace array code - Fix incorrect reporting of function_graph fields in format file - Fix quote within quote parsing in bootconfig - Fix return value of bootconfig tool - Add testcases for bootconfig tool - Fix maybe uninitialized warning in ftrace pid file code - Remove unused variable in tracing_iter_reset() - Fix some typos * tag 'trace-v5.8-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: ftrace: Fix maybe-uninitialized compiler warning tools/bootconfig: Add testcase for show-command and quotes test tools/bootconfig: Fix to return 0 if succeeded to show the bootconfig tools/bootconfig: Fix to use correct quotes for value proc/bootconfig: Fix to use correct quotes for value tracing: Remove unused event variable in tracing_iter_reset tracing/probe: Fix memleak in fetch_op_data operations trace: Fix typo in allocate_ftrace_ops()'s comment tracing: Make ftrace packed events have align of 1 sample-trace-array: Remove trace_array 'sample-instance' sample-trace-array: Fix sleeping function called from invalid context kretprobe: Prevent triggering kretprobe from within kprobe_flush_task kprobes: Remove redundant arch_disarm_kprobe() call kprobes: Fix to protect kick_kprobe_optimizer() by kprobe_mutex kprobes: Use non RCU traversal APIs on kprobe_tables if possible kprobes: Suppress the suspicious RCU warning on kprobes recordmcount: support >64k sections
2020-06-19Merge tag 'block-5.8-2020-06-19' of git://git.kernel.dk/linux-blockLinus Torvalds1-10/+20
Pull block fixes from Jens Axboe: - Use import_uuid() where appropriate (Andy) - bcache fixes (Coly, Mauricio, Zhiqiang) - blktrace sparse warnings fix (Jan) - blktrace concurrent setup fix (Luis) - blkdev_get use-after-free fix (Jason) - Ensure all blk-mq maps are updated (Weiping) - Loop invalidate bdev fix (Zheng) * tag 'block-5.8-2020-06-19' of git://git.kernel.dk/linux-block: block: make function 'kill_bdev' static loop: replace kill_bdev with invalidate_bdev partitions/ldm: Replace uuid_copy() with import_uuid() where it makes sense block: update hctx map when use multiple maps blktrace: Avoid sparse warnings when assigning q->blk_trace blktrace: break out of blktrace setup on concurrent calls block: Fix use-after-free in blkdev_get() trace/events/block.h: drop kernel-doc for dropped function parameter blk-mq: Remove redundant 'return' statement bcache: pr_info() format clean up in bcache_device_init() bcache: use delayed kworker fo asynchronous devices registration bcache: check and adjust logical block size for backing devices bcache: fix potential deadlock problem in btree_gc_coalesce
2020-06-18Merge branch 'hch' (maccess patches from Christoph Hellwig)Linus Torvalds2-7/+7
Merge non-faulting memory access cleanups from Christoph Hellwig: "Andrew and I decided to drop the patches implementing your suggested rename of the probe_kernel_* and probe_user_* helpers from -mm as there were way to many conflicts. After -rc1 might be a good time for this as all the conflicts are resolved now" This also adds a type safety checking patch on top of the renaming series to make the subtle behavioral difference between 'get_user()' and 'get_kernel_nofault()' less potentially dangerous and surprising. * emailed patches from Christoph Hellwig <[email protected]>: maccess: make get_kernel_nofault() check for minimal type compatibility maccess: rename probe_kernel_address to get_kernel_nofault maccess: rename probe_user_{read,write} to copy_{from,to}_user_nofault maccess: rename probe_kernel_{read,write} to copy_{from,to}_kernel_nofault
2020-06-17ftrace: Fix maybe-uninitialized compiler warningKaitao Cheng1-2/+10
During build compiler reports some 'false positive' warnings about variables {'seq_ops', 'filtered_pids', 'other_pids'} may be used uninitialized. This patch silences these warnings. Also delete some useless spaces Link: https://lkml.kernel.org/r/[email protected] Signed-off-by: Kaitao Cheng <[email protected]> Signed-off-by: Steven Rostedt (VMware) <[email protected]>
2020-06-17Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpfDavid S. Miller1-1/+1
Alexei Starovoitov says: ==================== pull-request: bpf 2020-06-17 The following pull-request contains BPF updates for your *net* tree. We've added 10 non-merge commits during the last 2 day(s) which contain a total of 14 files changed, 158 insertions(+), 59 deletions(-). The main changes are: 1) Important fix for bpf_probe_read_kernel_str() return value, from Andrii. 2) [gs]etsockopt fix for large optlen, from Stanislav. 3) devmap allocation fix, from Toke. ==================== Signed-off-by: David S. Miller <[email protected]>
2020-06-17maccess: rename probe_user_{read,write} to copy_{from,to}_user_nofaultChristoph Hellwig2-3/+3
Better describe what these functions do. Suggested-by: Linus Torvalds <[email protected]> Signed-off-by: Christoph Hellwig <[email protected]> Signed-off-by: Linus Torvalds <[email protected]>
2020-06-17maccess: rename probe_kernel_{read,write} to copy_{from,to}_kernel_nofaultChristoph Hellwig2-4/+4
Better describe what these functions do. Suggested-by: Linus Torvalds <[email protected]> Signed-off-by: Christoph Hellwig <[email protected]> Signed-off-by: Linus Torvalds <[email protected]>