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There's currently a way to select a task that should only have its events
traced, but there's no way to select a task not to have itsevents traced.
Add a set_event_notrace_pid file that acts the same as set_event_pid (and is
also affected by event-fork), but the task pids in this file will not be
traced even if they are listed in the set_event_pid file. This makes it easy
for tools like trace-cmd to "hide" itself from beint traced by events when
it is recording other tasks.
Signed-off-by: Steven Rostedt (VMware) <[email protected]>
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There's currently a way to select a task that should only be traced by
functions, but there's no way to select a task not to be traced by the
function tracer. Add a set_ftrace_notrace_pid file that acts the same as
set_ftrace_pid (and is also affected by function-fork), but the task pids in
this file will not be traced even if they are listed in the set_ftrace_pid
file. This makes it easy for tools like trace-cmd to "hide" itself from the
function tracer when it is recording other tasks.
Signed-off-by: Steven Rostedt (VMware) <[email protected]>
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The set_ftrace_pid file is used to filter function tracing to only trace
tasks that are listed in that file. Instead of testing the pids listed in
that file (it's a bitmask) at each function trace event, the logic is done
via a sched_switch hook. A flag is set when the next task to run is in the
list of pids in the set_ftrace_pid file. But the sched_switch hook is not at
the exact location of when the task switches, and the flag gets set before
the task to be traced actually runs. This leaves a residue of traced
functions that do not belong to the pid that should be filtered on.
By changing the logic slightly, where instead of having a boolean flag to
test, record the pid that should be traced, with special values for not to
trace and always trace. Then at each function call, a check will be made to
see if the function should be ignored, or if the current pid matches the
function that should be traced, and only trace if it matches (or if it has
the special value to always trace).
Signed-off-by: Steven Rostedt (VMware) <[email protected]>
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Show maxactive parameter on kprobe_events.
This allows user to save the current configuration and
restore it without losing maxactive parameter.
Link: http://lkml.kernel.org/r/[email protected]
Link: http://lkml.kernel.org/r/158503528846.22706.5549974121212526020.stgit@devnote2
Cc: [email protected]
Fixes: 696ced4fb1d76 ("tracing/kprobes: expose maxactive for kretprobe in kprobe_events")
Reported-by: Taeung Song <[email protected]>
Signed-off-by: Masami Hiramatsu <[email protected]>
Signed-off-by: Steven Rostedt (VMware) <[email protected]>
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Have the ring_buffer_iterator set a flag if events were dropped as it were
to go and peek at the next event. Have the trace file display this fact if
it happened with a "LOST EVENTS" message.
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Steven Rostedt (VMware) <[email protected]>
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When opening the "trace" file, it is no longer necessary to disable tracing.
Note, a new option is created called "pause-on-trace", when set, will cause
the trace file to emulate its original behavior.
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Steven Rostedt (VMware) <[email protected]>
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Now that the iterator can handle a concurrent writer, do not disable writing
to the ring buffer when there is an iterator present.
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Steven Rostedt (VMware) <[email protected]>
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When the ring buffer becomes writable for even when the trace file is read,
it must still not be resized. But since tracers can be activated while the
trace file is being read, the irqsoff tracer can modify the per CPU buffers,
and this can cause the reader of the trace file to update the wrong buffer's
resize disable bit, as the irqsoff tracer swaps out cpu buffers.
By making the resize disable per cpu_buffer, it makes the update follow the
per cpu_buffer even if it's swapped out with the snapshot buffer and keeps
the release of the trace file modifying the same data as the open did.
Signed-off-by: Steven Rostedt (VMware) <[email protected]>
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The PERF_SAMPLE_CGROUP bit is to save (perf_event) cgroup information in
the sample. It will add a 64-bit id to identify current cgroup and it's
the file handle in the cgroup file system. Userspace should use this
information with PERF_RECORD_CGROUP event to match which cgroup it
belongs.
I put it before PERF_SAMPLE_AUX for simplicity since it just needs a
64-bit word. But if we want bigger samples, I can work on that
direction too.
Committer testing:
$ pahole perf_sample_data | grep -w cgroup -B5 -A5
/* --- cacheline 4 boundary (256 bytes) was 56 bytes ago --- */
struct perf_regs regs_intr; /* 312 16 */
/* --- cacheline 5 boundary (320 bytes) was 8 bytes ago --- */
u64 stack_user_size; /* 328 8 */
u64 phys_addr; /* 336 8 */
u64 cgroup; /* 344 8 */
/* size: 384, cachelines: 6, members: 22 */
/* padding: 32 */
};
$
Signed-off-by: Namhyung Kim <[email protected]>
Tested-by: Arnaldo Carvalho de Melo <[email protected]>
Acked-by: Peter Zijlstra (Intel) <[email protected]>
Acked-by: Tejun Heo <[email protected]>
Cc: Alexander Shishkin <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Johannes Weiner <[email protected]>
Cc: Mark Rutland <[email protected]>
Cc: Zefan Li <[email protected]>
Link: http://lore.kernel.org/lkml/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
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To support cgroup tracking, add CGROUP event to save a link between
cgroup path and id number. This is needed since cgroups can go away
when userspace tries to read the cgroup info (from the id) later.
The attr.cgroup bit was also added to enable cgroup tracking from
userspace.
This event will be generated when a new cgroup becomes active.
Userspace might need to synthesize those events for existing cgroups.
Committer testing:
From the resulting kernel, using /sys/kernel/btf/vmlinux:
$ pahole perf_event_attr | grep -w cgroup -B5 -A1
__u64 write_backward:1; /* 40:27 8 */
__u64 namespaces:1; /* 40:28 8 */
__u64 ksymbol:1; /* 40:29 8 */
__u64 bpf_event:1; /* 40:30 8 */
__u64 aux_output:1; /* 40:31 8 */
__u64 cgroup:1; /* 40:32 8 */
__u64 __reserved_1:31; /* 40:33 8 */
$
Reported-by: kbuild test robot <[email protected]>
Signed-off-by: Namhyung Kim <[email protected]>
Tested-by: Arnaldo Carvalho de Melo <[email protected]>
Acked-by: Peter Zijlstra (Intel) <[email protected]>
Acked-by: Tejun Heo <[email protected]>
[staticize perf_event_cgroup function]
Cc: Adrian Hunter <[email protected]>
Cc: Alexander Shishkin <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Johannes Weiner <[email protected]>
Cc: Mark Rutland <[email protected]>
Cc: Zefan Li <[email protected]>
Link: http://lore.kernel.org/lkml/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
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kernel/bpf/syscall.c:2263:34: warning: 'bpf_xdp_link_lops' defined but not used [-Wunused-const-variable=]
static const struct bpf_link_ops bpf_xdp_link_lops;
^~~~~~~~~~~~~~~~~
commit 70ed506c3bbc ("bpf: Introduce pinnable bpf_link abstraction")
involded this unused variable, remove it.
Reported-by: Hulk Robot <[email protected]>
Signed-off-by: YueHaibing <[email protected]>
Signed-off-by: Alexei Starovoitov <[email protected]>
Acked-by: Andrii Nakryiko <[email protected]>
Link: https://lore.kernel.org/bpf/[email protected]
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Factor out logic mapping expected program attach type to program type and
subsequent handling of program attach/detach. Also list out all supported
cgroup BPF program types explicitly to prevent accidental bugs once more
program types are added to a mapping. Do the same for prog_query API.
Signed-off-by: Andrii Nakryiko <[email protected]>
Signed-off-by: Alexei Starovoitov <[email protected]>
Link: https://lore.kernel.org/bpf/[email protected]
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Refactor cgroup attach/detach code to abstract away common operations
performed on all types of cgroup storages. This makes high-level logic more
apparent, plus allows to reuse more code across multiple functions.
Signed-off-by: Andrii Nakryiko <[email protected]>
Signed-off-by: Alexei Starovoitov <[email protected]>
Link: https://lore.kernel.org/bpf/[email protected]
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Currently, for all op verification we call __red_deduce_bounds() and
__red_bound_offset() but we only call __update_reg_bounds() in bitwise
ops. However, we could benefit from calling __update_reg_bounds() in
BPF_ADD, BPF_SUB, and BPF_MUL cases as well.
For example, a register with state 'R1_w=invP0' when we subtract from
it,
w1 -= 2
Before coerce we will now have an smin_value=S64_MIN, smax_value=U64_MAX
and unsigned bounds umin_value=0, umax_value=U64_MAX. These will then
be clamped to S32_MIN, U32_MAX values by coerce in the case of alu32 op
as done in above example. However tnum will be a constant because the
ALU op is done on a constant.
Without update_reg_bounds() we have a scenario where tnum is a const
but our unsigned bounds do not reflect this. By calling update_reg_bounds
after coerce to 32bit we further refine the umin_value to U64_MAX in the
alu64 case or U32_MAX in the alu32 case above.
Signed-off-by: John Fastabend <[email protected]>
Signed-off-by: Alexei Starovoitov <[email protected]>
Link: https://lore.kernel.org/bpf/158507151689.15666.566796274289413203.stgit@john-Precision-5820-Tower
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Pull per op ALU logic into individual functions. We are about to add
u32 versions of each of these by pull them out the code gets a bit
more readable here and nicer in the next patch.
Signed-off-by: John Fastabend <[email protected]>
Signed-off-by: Alexei Starovoitov <[email protected]>
Link: https://lore.kernel.org/bpf/158507149518.15666.15672349629329072411.stgit@john-Precision-5820-Tower
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Overlapping header include additions in macsec.c
A bug fix in 'net' overlapping with the removal of 'version'
string in ena_netdev.c
Overlapping test additions in selftests Makefile
Overlapping PCI ID table adjustments in iwlwifi driver.
Signed-off-by: David S. Miller <[email protected]>
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Pull networking fixes from David Miller:
1) Fix deadlock in bpf_send_signal() from Yonghong Song.
2) Fix off by one in kTLS offload of mlx5, from Tariq Toukan.
3) Add missing locking in iwlwifi mvm code, from Avraham Stern.
4) Fix MSG_WAITALL handling in rxrpc, from David Howells.
5) Need to hold RTNL mutex in tcindex_partial_destroy_work(), from Cong
Wang.
6) Fix producer race condition in AF_PACKET, from Willem de Bruijn.
7) cls_route removes the wrong filter during change operations, from
Cong Wang.
8) Reject unrecognized request flags in ethtool netlink code, from
Michal Kubecek.
9) Need to keep MAC in reset until PHY is up in bcmgenet driver, from
Doug Berger.
10) Don't leak ct zone template in act_ct during replace, from Paul
Blakey.
11) Fix flushing of offloaded netfilter flowtable flows, also from Paul
Blakey.
12) Fix throughput drop during tx backpressure in cxgb4, from Rahul
Lakkireddy.
13) Don't let a non-NULL skb->dev leave the TCP stack, from Eric
Dumazet.
14) TCP_QUEUE_SEQ socket option has to update tp->copied_seq as well,
also from Eric Dumazet.
15) Restrict macsec to ethernet devices, from Willem de Bruijn.
16) Fix reference leak in some ethtool *_SET handlers, from Michal
Kubecek.
17) Fix accidental disabling of MSI for some r8169 chips, from Heiner
Kallweit.
* git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net: (138 commits)
net: Fix CONFIG_NET_CLS_ACT=n and CONFIG_NFT_FWD_NETDEV={y, m} build
net: ena: Add PCI shutdown handler to allow safe kexec
selftests/net/forwarding: define libs as TEST_PROGS_EXTENDED
selftests/net: add missing tests to Makefile
r8169: re-enable MSI on RTL8168c
net: phy: mdio-bcm-unimac: Fix clock handling
cxgb4/ptp: pass the sign of offset delta in FW CMD
net: dsa: tag_8021q: replace dsa_8021q_remove_header with __skb_vlan_pop
net: cbs: Fix software cbs to consider packet sending time
net/mlx5e: Do not recover from a non-fatal syndrome
net/mlx5e: Fix ICOSQ recovery flow with Striding RQ
net/mlx5e: Fix missing reset of SW metadata in Striding RQ reset
net/mlx5e: Enhance ICOSQ WQE info fields
net/mlx5_core: Set IB capability mask1 to fix ib_srpt connection failure
selftests: netfilter: add nfqueue test case
netfilter: nft_fwd_netdev: allow to redirect to ifb via ingress
netfilter: nft_fwd_netdev: validate family and chain type
netfilter: nft_set_rbtree: Detect partial overlaps on insertion
netfilter: nft_set_rbtree: Introduce and use nft_rbtree_interval_start()
netfilter: nft_set_pipapo: Separate partial and complete overlap cases on insertion
...
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This changes __pidfd_fget to use the new exec_update_mutex
instead of cred_guard_mutex.
This should be safe, as the credentials do not change
before exec_update_mutex is locked. Therefore whatever
file access is possible with holding the cred_guard_mutex
here is also possbile with the exec_update_mutex.
Signed-off-by: Bernd Edlinger <[email protected]>
Signed-off-by: Eric W. Biederman <[email protected]>
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This changes perf_event_set_clock to use the new exec_update_mutex
instead of cred_guard_mutex.
This should be safe, as the credentials are only used for reading.
Signed-off-by: Bernd Edlinger <[email protected]>
Signed-off-by: Eric W. Biederman <[email protected]>
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This changes kcmp_epoll_target to use the new exec_update_mutex
instead of cred_guard_mutex.
This should be safe, as the credentials are only used for reading,
and furthermore ->mm and ->sighand are updated on execve,
but only under the new exec_update_mutex.
Signed-off-by: Bernd Edlinger <[email protected]>
Signed-off-by: Eric W. Biederman <[email protected]>
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This removes an outdated comment in prepare_kernel_cred.
There is no "cred_replace_mutex" any more, so the comment must
go away.
Signed-off-by: Bernd Edlinger <[email protected]>
Reviewed-by: Kees Cook <[email protected]>
Signed-off-by: Eric W. Biederman <[email protected]>
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This fixes a deadlock in the tracer when tracing a multi-threaded
application that calls execve while more than one thread are running.
I observed that when running strace on the gcc test suite, it always
blocks after a while, when expect calls execve, because other threads
have to be terminated. They send ptrace events, but the strace is no
longer able to respond, since it is blocked in vm_access.
The deadlock is always happening when strace needs to access the
tracees process mmap, while another thread in the tracee starts to
execve a child process, but that cannot continue until the
PTRACE_EVENT_EXIT is handled and the WIFEXITED event is received:
strace D 0 30614 30584 0x00000000
Call Trace:
__schedule+0x3ce/0x6e0
schedule+0x5c/0xd0
schedule_preempt_disabled+0x15/0x20
__mutex_lock.isra.13+0x1ec/0x520
__mutex_lock_killable_slowpath+0x13/0x20
mutex_lock_killable+0x28/0x30
mm_access+0x27/0xa0
process_vm_rw_core.isra.3+0xff/0x550
process_vm_rw+0xdd/0xf0
__x64_sys_process_vm_readv+0x31/0x40
do_syscall_64+0x64/0x220
entry_SYSCALL_64_after_hwframe+0x44/0xa9
expect D 0 31933 30876 0x80004003
Call Trace:
__schedule+0x3ce/0x6e0
schedule+0x5c/0xd0
flush_old_exec+0xc4/0x770
load_elf_binary+0x35a/0x16c0
search_binary_handler+0x97/0x1d0
__do_execve_file.isra.40+0x5d4/0x8a0
__x64_sys_execve+0x49/0x60
do_syscall_64+0x64/0x220
entry_SYSCALL_64_after_hwframe+0x44/0xa9
This changes mm_access to use the new exec_update_mutex
instead of cred_guard_mutex.
This patch is based on the following patch by Eric W. Biederman:
"[PATCH 0/5] Infrastructure to allow fixing exec deadlocks"
Link: https://lore.kernel.org/lkml/[email protected]/
Signed-off-by: Bernd Edlinger <[email protected]>
Reviewed-by: Kees Cook <[email protected]>
Signed-off-by: Eric W. Biederman <[email protected]>
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The cred_guard_mutex is problematic as it is held over possibly
indefinite waits for userspace. The possible indefinite waits for
userspace that I have identified are: The cred_guard_mutex is held in
PTRACE_EVENT_EXIT waiting for the tracer. The cred_guard_mutex is
held over "put_user(0, tsk->clear_child_tid)" in exit_mm(). The
cred_guard_mutex is held over "get_user(futex_offset, ...") in
exit_robust_list. The cred_guard_mutex held over copy_strings.
The functions get_user and put_user can trigger a page fault which can
potentially wait indefinitely in the case of userfaultfd or if
userspace implements part of the page fault path.
In any of those cases the userspace process that the kernel is waiting
for might make a different system call that winds up taking the
cred_guard_mutex and result in deadlock.
Holding a mutex over any of those possibly indefinite waits for
userspace does not appear necessary. Add exec_update_mutex that will
just cover updating the process during exec where the permissions and
the objects pointed to by the task struct may be out of sync.
The plan is to switch the users of cred_guard_mutex to
exec_update_mutex one by one. This lets us move forward while still
being careful and not introducing any regressions.
Link: https://lore.kernel.org/lkml/[email protected]/
Link: https://lore.kernel.org/lkml/AM6PR03MB5170B06F3A2B75EFB98D071AE4E60@AM6PR03MB5170.eurprd03.prod.outlook.com/
Link: https://lore.kernel.org/linux-fsdevel/[email protected]/
Link: https://lore.kernel.org/lkml/[email protected]/
Link: https://lore.kernel.org/lkml/[email protected]/
Ref: 45c1a159b85b ("Add PTRACE_O_TRACEVFORKDONE and PTRACE_O_TRACEEXIT facilities.")
Ref: 456f17cd1a28 ("[PATCH] user-vm-unlock-2.5.31-A2")
Reviewed-by: Kirill Tkhai <[email protected]>
Signed-off-by: "Eric W. Biederman" <[email protected]>
Signed-off-by: Bernd Edlinger <[email protected]>
Signed-off-by: Eric W. Biederman <[email protected]>
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Use separate functions for the device core to bring a CPU up and down.
Users outside the device core must use add/remove_cpu() which will take
care of extra housekeeping work like keeping sysfs in sync.
Make cpu_up/down() static and replace the extra layer of indirection.
[ tglx: Removed the extra wrapper functions and adjusted function names ]
Signed-off-by: Qais Yousef <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]
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This is the last direct user of cpu_up() before it can become an internal
implementation detail of the cpu subsystem.
Signed-off-by: Qais Yousef <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]
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The core device API performs extra housekeeping bits that are missing
from directly calling cpu_up/down().
See commit a6717c01ddc2 ("powerpc/rtas: use device model APIs and
serialization during LPM") for an example description of what might go
wrong.
This also prepares to make cpu_up/down() a private interface of the CPU
subsystem.
Signed-off-by: Qais Yousef <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Acked-by: "Paul E. McKenney" <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]
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arm64 uses cpu_up() in the resume from hibernation code to ensure that the
CPU on which the system hibernated is online. Provide a core function for
this.
[ tglx: Split out from the combo arm64 patch ]
Signed-off-by: Qais Yousef <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Acked-by: Catalin Marinas <[email protected]>
Cc: Will Deacon <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]
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This function will be used later in machine_shutdown() for some
architectures.
disable_nonboot_cpus() is not safe to use when doing machine_down(),
because it relies on freeze_secondary_cpus() which in turn is a
suspend/resume related freeze and could abort if the logic detects any
pending activities that can prevent finishing the offlining process.
Signed-off-by: Qais Yousef <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]
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The new functions use device_{online,offline}() which are userspace safe.
This is in preparation to move cpu_{up, down} kernel users to use a safer
interface that is not racy with userspace.
Suggested-by: "Paul E. McKenney" <[email protected]>
Signed-off-by: Qais Yousef <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Reviewed-by: Paul E. McKenney <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]
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Add SPDX License Identifier to all .gitignore files.
Signed-off-by: Masahiro Yamada <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
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Some .gitignore files have comments like "Generated files",
"Ignore generated files" at the header part, but they are
too obvious.
Signed-off-by: Masahiro Yamada <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
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git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu into core/rcu
Pull RCU changes from Paul E. McKenney:
- Make kfree_rcu() use kfree_bulk() for added performance
- RCU updates
- Callback-overload handling updates
- Tasks-RCU KCSAN and sparse updates
- Locking torture test and RCU torture test updates
- Documentation updates
- Miscellaneous fixes
Signed-off-by: Ingo Molnar <[email protected]>
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The warning was intended to spot complete_all() users from hardirq
context on PREEMPT_RT. The warning as-is will also trigger in interrupt
handlers, which are threaded on PREEMPT_RT, which was not intended.
Use lockdep_assert_RT_in_threaded_ctx() which triggers in non-preemptive
context on PREEMPT_RT.
Fixes: a5c6234e1028 ("completion: Use simple wait queues")
Reported-by: kernel test robot <[email protected]>
Suggested-by: Peter Zijlstra <[email protected]>
Signed-off-by: Sebastian Andrzej Siewior <[email protected]>
Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]
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Create helpers to access path and inode from different data types.
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Amir Goldstein <[email protected]>
Signed-off-by: Jan Kara <[email protected]>
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ARCH_SAVE_PAGE_KEYS has been introduced in order to be able to save
and restore s390 specific storage keys into a hibernation image.
With hibernation support removed from s390 there is no point in
keeping the callbacks.
Acked-by: Christian Borntraeger <[email protected]>
Acked-by: Peter Oberparleiter <[email protected]>
Signed-off-by: Heiko Carstens <[email protected]>
Signed-off-by: Vasily Gorbik <[email protected]>
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We need the tty fixes in here as well.
Signed-off-by: Greg Kroah-Hartman <[email protected]>
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We need the char/misc driver fixes in here as well.
Signed-off-by: Greg Kroah-Hartman <[email protected]>
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Commit 3f8fd02b1bf1 ("mm/vmalloc: Sync unmappings in
__purge_vmap_area_lazy()") introduced a call to vmalloc_sync_all() in
the vunmap() code-path. While this change was necessary to maintain
correctness on x86-32-pae kernels, it also adds additional cycles for
architectures that don't need it.
Specifically on x86-64 with CONFIG_VMAP_STACK=y some people reported
severe performance regressions in micro-benchmarks because it now also
calls the x86-64 implementation of vmalloc_sync_all() on vunmap(). But
the vmalloc_sync_all() implementation on x86-64 is only needed for newly
created mappings.
To avoid the unnecessary work on x86-64 and to gain the performance
back, split up vmalloc_sync_all() into two functions:
* vmalloc_sync_mappings(), and
* vmalloc_sync_unmappings()
Most call-sites to vmalloc_sync_all() only care about new mappings being
synchronized. The only exception is the new call-site added in the
above mentioned commit.
Shile Zhang directed us to a report of an 80% regression in reaim
throughput.
Fixes: 3f8fd02b1bf1 ("mm/vmalloc: Sync unmappings in __purge_vmap_area_lazy()")
Reported-by: kernel test robot <[email protected]>
Reported-by: Shile Zhang <[email protected]>
Signed-off-by: Joerg Roedel <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Tested-by: Borislav Petkov <[email protected]>
Acked-by: Rafael J. Wysocki <[email protected]> [GHES]
Cc: Dave Hansen <[email protected]>
Cc: Andy Lutomirski <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Link: https://lists.01.org/hyperkitty/list/[email protected]/thread/4D3JPPHBNOSPFK2KEPC6KGKS6J25AIDB/
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Linus Torvalds <[email protected]>
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'kfree_rcu.2020.02.20a', 'locktorture.2020.02.20a', 'ovld.2020.02.20a', 'rcu-tasks.2020.02.20a', 'srcu.2020.02.20a' and 'torture.2020.02.20a' into HEAD
doc.2020.02.27a: Documentation updates.
fixes.2020.03.21a: Miscellaneous fixes.
kfree_rcu.2020.02.20a: Updates to kfree_rcu().
locktorture.2020.02.20a: Lock torture-test updates.
ovld.2020.02.20a: Updates to callback-overload handling.
rcu-tasks.2020.02.20a: RCU-tasks updates.
srcu.2020.02.20a: SRCU updates.
torture.2020.02.20a: Torture-test updates.
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Currently, rcu_barrier() ignores offline CPUs, However, it is possible
for an offline no-CBs CPU to have callbacks queued, and rcu_barrier()
must wait for those callbacks. This commit therefore makes rcu_barrier()
directly invoke the rcu_barrier_func() with interrupts disabled for such
CPUs. This requires passing the CPU number into this function so that
it can entrain the rcu_barrier() callback onto the correct CPU's callback
list, given that the code must instead execute on the current CPU.
While in the area, this commit fixes a bug where the first CPU's callback
might have been invoked before rcu_segcblist_entrain() returned, which
would also result in an early wakeup.
Fixes: 5d6742b37727 ("rcu/nocb: Use rcu_segcblist for no-CBs CPUs")
Signed-off-by: Paul E. McKenney <[email protected]>
[ paulmck: Apply optimization feedback from Boqun Feng. ]
Cc: <[email protected]> # 5.5.x
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The rcu_state structure's gp_seq field is only to be modified by the RCU
grace-period kthread, which is single-threaded. This commit therefore
enlists KCSAN's help in enforcing this restriction.
Signed-off-by: Paul E. McKenney <[email protected]>
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The handling of notify->work did not properly maintain notify->kref in two
cases:
1) where the work was already scheduled, another irq_set_affinity_locked()
would get the ref and (no-op-ly) schedule the work. Thus when
irq_affinity_notify() ran, it would drop the original ref but not the
additional one.
2) when cancelling the (old) work in irq_set_affinity_notifier(), if there
was outstanding work a ref had been got for it but was never put.
Fix both by checking the return values of the work handling functions
(schedule_work() for (1) and cancel_work_sync() for (2)) and put the
extra ref if the return value indicates preexisting work.
Fixes: cd7eab44e994 ("genirq: Add IRQ affinity notifiers")
Fixes: 59c39840f5ab ("genirq: Prevent use-after-free and work list corruption")
Signed-off-by: Edward Cree <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Acked-by: Ben Hutchings <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]
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Continue what commit:
d820ac4c2fa8 ("locking: rename trace_softirq_[enter|exit] => lockdep_softirq_[enter|exit]")
started, rename these to avoid confusing them with tracepoints.
git grep -l "trace_\(soft\|hard\)\(irq_context\|irqs_enabled\)" | while read file;
do
sed -ie 's/trace_\(soft\|hard\)\(irq_context\|irqs_enabled\)/lockdep_\1\2/g' $file;
done
Reported-by: Thomas Gleixner <[email protected]>
Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Reviewed-by: Thomas Gleixner <[email protected]>
Acked-by: Will Deacon <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]
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Continue what commit:
d820ac4c2fa8 ("locking: rename trace_softirq_[enter|exit] => lockdep_softirq_[enter|exit]")
started, rename these to avoid confusing them with tracepoints.
git grep -l "trace_softirqs_\(on\|off\)" | while read file;
do
sed -ie 's/trace_softirqs_\(on\|off\)/lockdep_softirqs_\1/g' $file;
done
Reported-by: Thomas Gleixner <[email protected]>
Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Reviewed-by: Thomas Gleixner <[email protected]>
Acked-by: Will Deacon <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]
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Continue what commit:
d820ac4c2fa8 ("locking: rename trace_softirq_[enter|exit] => lockdep_softirq_[enter|exit]")
started, rename these to avoid confusing them with tracepoints.
Signed-off-by: Thomas Gleixner <[email protected]>
Reviewed-by: Thomas Gleixner <[email protected]>
Acked-by: Will Deacon <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]
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Splitting run_posix_cpu_timers() into two parts is work in progress which
is stuck on other entry code related problems. The heavy lifting which
involves locking of sighand lock will be moved into task context so the
necessary execution time is burdened on the task and not on interrupt
context.
Until this work completes lockdep with the spinlock nesting rules enabled
would emit warnings for this known context.
Prevent it by setting "->irq_config = 1" for the invocation of
run_posix_cpu_timers() so lockdep does not complain when sighand lock is
acquried. This will be removed once the split is completed.
Signed-off-by: Sebastian Andrzej Siewior <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]
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Mark irq_work items with IRQ_WORK_HARD_IRQ which should be invoked in
hardirq context even on PREEMPT_RT. IRQ_WORK without this flag will be
invoked in softirq context on PREEMPT_RT.
Set ->irq_config to 1 for the IRQ_WORK items which are invoked in softirq
context so lockdep knows that these can safely acquire a spinlock_t.
Signed-off-by: Sebastian Andrzej Siewior <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]
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Set current->irq_config = 1 for hrtimers which are not marked to expire in
hard interrupt context during hrtimer_init(). These timers will expire in
softirq context on PREEMPT_RT.
Setting this allows lockdep to differentiate these timers. If a timer is
marked to expire in hard interrupt context then the timer callback is not
supposed to acquire a regular spinlock instead of a raw_spinlock in the
expiry callback.
Signed-off-by: Sebastian Andrzej Siewior <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]
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Extend lockdep to validate lock wait-type context.
The current wait-types are:
LD_WAIT_FREE, /* wait free, rcu etc.. */
LD_WAIT_SPIN, /* spin loops, raw_spinlock_t etc.. */
LD_WAIT_CONFIG, /* CONFIG_PREEMPT_LOCK, spinlock_t etc.. */
LD_WAIT_SLEEP, /* sleeping locks, mutex_t etc.. */
Where lockdep validates that the current lock (the one being acquired)
fits in the current wait-context (as generated by the held stack).
This ensures that there is no attempt to acquire mutexes while holding
spinlocks, to acquire spinlocks while holding raw_spinlocks and so on. In
other words, its a more fancy might_sleep().
Obviously RCU made the entire ordeal more complex than a simple single
value test because RCU can be acquired in (pretty much) any context and
while it presents a context to nested locks it is not the same as it
got acquired in.
Therefore its necessary to split the wait_type into two values, one
representing the acquire (outer) and one representing the nested context
(inner). For most 'normal' locks these two are the same.
[ To make static initialization easier we have the rule that:
.outer == INV means .outer == .inner; because INV == 0. ]
It further means that its required to find the minimal .inner of the held
stack to compare against the outer of the new lock; because while 'normal'
RCU presents a CONFIG type to nested locks, if it is taken while already
holding a SPIN type it obviously doesn't relax the rules.
Below is an example output generated by the trivial test code:
raw_spin_lock(&foo);
spin_lock(&bar);
spin_unlock(&bar);
raw_spin_unlock(&foo);
[ BUG: Invalid wait context ]
-----------------------------
swapper/0/1 is trying to lock:
ffffc90000013f20 (&bar){....}-{3:3}, at: kernel_init+0xdb/0x187
other info that might help us debug this:
1 lock held by swapper/0/1:
#0: ffffc90000013ee0 (&foo){+.+.}-{2:2}, at: kernel_init+0xd1/0x187
The way to read it is to look at the new -{n,m} part in the lock
description; -{3:3} for the attempted lock, and try and match that up to
the held locks, which in this case is the one: -{2,2}.
This tells that the acquiring lock requires a more relaxed environment than
presented by the lock stack.
Currently only the normal locks and RCU are converted, the rest of the
lockdep users defaults to .inner = INV which is ignored. More conversions
can be done when desired.
The check for spinlock_t nesting is not enabled by default. It's a separate
config option for now as there are known problems which are currently
addressed. The config option allows to identify these problems and to
verify that the solutions found are indeed solving them.
The config switch will be removed and the checks will permanently enabled
once the vast majority of issues has been addressed.
[ bigeasy: Move LD_WAIT_FREE,… out of CONFIG_LOCKDEP to avoid compile
failure with CONFIG_DEBUG_SPINLOCK + !CONFIG_LOCKDEP]
[ tglx: Add the config option ]
Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Signed-off-by: Sebastian Andrzej Siewior <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]
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completion uses a wait_queue_head_t to enqueue waiters.
wait_queue_head_t contains a spinlock_t to protect the list of waiters
which excludes it from being used in truly atomic context on a PREEMPT_RT
enabled kernel.
The spinlock in the wait queue head cannot be replaced by a raw_spinlock
because:
- wait queues can have custom wakeup callbacks, which acquire other
spinlock_t locks and have potentially long execution times
- wake_up() walks an unbounded number of list entries during the wake up
and may wake an unbounded number of waiters.
For simplicity and performance reasons complete() should be usable on
PREEMPT_RT enabled kernels.
completions do not use custom wakeup callbacks and are usually single
waiter, except for a few corner cases.
Replace the wait queue in the completion with a simple wait queue (swait),
which uses a raw_spinlock_t for protecting the waiter list and therefore is
safe to use inside truly atomic regions on PREEMPT_RT.
There is no semantical or functional change:
- completions use the exclusive wait mode which is what swait provides
- complete() wakes one exclusive waiter
- complete_all() wakes all waiters while holding the lock which protects
the wait queue against newly incoming waiters. The conversion to swait
preserves this behaviour.
complete_all() might cause unbound latencies with a large number of waiters
being woken at once, but most complete_all() usage sites are either in
testing or initialization code or have only a really small number of
concurrent waiters which for now does not cause a latency problem. Keep it
simple for now.
The fixup of the warning check in the USB gadget driver is just a straight
forward conversion of the lockless waiter check from one waitqueue type to
the other.
Signed-off-by: Thomas Gleixner <[email protected]>
Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Reviewed-by: Greg Kroah-Hartman <[email protected]>
Reviewed-by: Davidlohr Bueso <[email protected]>
Reviewed-by: Joel Fernandes (Google) <[email protected]>
Acked-by: Linus Torvalds <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]
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