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My commit b0c51f158455 ("stacktrace: Don't skip first entry on
noncurrent tasks") adds one or zero to skipnr by "!!(current == tsk)".
But the C99 standard says:
The == (equal to) and != (not equal to) operators are
...
Each of the operators yields 1 if the specified relation is true and 0
if it is false.
So there is no need to prepend the above expression by "!!" -- remove it.
Reported-by: Joe Perches <[email protected]>
Signed-off-by: Jiri Slaby <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>
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When doing cat /proc/<PID>/stack, the output is missing the first entry.
When the current code walks the stack starting in stack_trace_save_tsk,
it skips all scheduler functions (that's OK) plus one more function. But
this one function should be skipped only for the 'current' task as it is
stack_trace_save_tsk proper.
The original code (before the common infrastructure) skipped one
function only for the 'current' task -- see save_stack_trace_tsk before
3599fe12a125. So do so also in the new infrastructure now.
Fixes: 214d8ca6ee85 ("stacktrace: Provide common infrastructure")
Signed-off-by: Jiri Slaby <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Tested-by: Michal Suchanek <[email protected]>
Acked-by: Josh Poimboeuf <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]
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Make it clear to humans and to the compiler that the stack trace
('entries') arguments are not modified.
Signed-off-by: Bart Van Assche <[email protected]>
Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Waiman Long <[email protected]>
Cc: Will Deacon <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>
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When walking userspace stacks, USER_DS needs to be set, otherwise
access_ok() will not function as expected.
Reported-by: Vegard Nossum <[email protected]>
Reported-by: Eiichi Tsukata <[email protected]>
Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Tested-by: Vegard Nossum <[email protected]>
Reviewed-by: Joel Fernandes (Google) <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]
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git://git.kernel.org/pub/scm/linux/kernel/git/livepatching/livepatching
Pull livepatching updates from Jiri Kosina:
- stacktrace handling improvements from Miroslav benes
- debug output improvements from Petr Mladek
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/livepatching/livepatching:
livepatch: Remove duplicate warning about missing reliable stacktrace support
Revert "livepatch: Remove reliable stacktrace check in klp_try_switch_task()"
stacktrace: Remove weak version of save_stack_trace_tsk_reliable()
livepatch: Use static buffer for debugging messages under rq lock
livepatch: Remove stale kobj_added entries from kernel-doc descriptions
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!current->mm is not a reliable indicator for kernel threads as they might
temporarily use a user mm. Check for PF_KTHREAD instead.
Signed-off-by: Thomas Gleixner <[email protected]>
Acked-by: Mark Rutland <[email protected]>
Cc: Josh Poimboeuf <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Steven Rostedt <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]
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Recent rework of stack trace infrastructure introduced a new set of
helpers for common stack trace operations (commit e9b98e162aa5
("stacktrace: Provide helpers for common stack trace operations") and
related). As a result, save_stack_trace_tsk_reliable() is not directly
called anywhere. Livepatch, currently the only user of the reliable
stack trace feature, now calls stack_trace_save_tsk_reliable().
When CONFIG_HAVE_RELIABLE_STACKTRACE is set and depending on
CONFIG_ARCH_STACKWALK, stack_trace_save_tsk_reliable() calls either
arch_stack_walk_reliable() or mentioned save_stack_trace_tsk_reliable().
x86_64 defines the former, ppc64le the latter. All other architectures
do not have HAVE_RELIABLE_STACKTRACE and include/linux/stacktrace.h
defines -ENOSYS returning version for them.
In short, stack_trace_save_tsk_reliable() returning -ENOSYS defined in
include/linux/stacktrace.h serves the same purpose as the old weak
version of save_stack_trace_tsk_reliable() which is therefore no longer
needed.
Signed-off-by: Miroslav Benes <[email protected]>
Acked-by: Josh Poimboeuf <[email protected]>
Reviewed-by: Thomas Gleixner <[email protected]>
Reviewed-by: Kamalesh Babulal <[email protected]>
Signed-off-by: Petr Mladek <[email protected]>
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull stacktrace fix from Ingo Molnar:
"Fix a stack_trace_save_tsk_reliable() regression"
* 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
stacktrace: Unbreak stack_trace_save_tsk_reliable()
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Add SPDX license identifiers to all files which:
- Have no license information of any form
- Have EXPORT_.*_SYMBOL_GPL inside which was used in the
initial scan/conversion to ignore the file
These files fall under the project license, GPL v2 only. The resulting SPDX
license identifier is:
GPL-2.0-only
Signed-off-by: Thomas Gleixner <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
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Miroslav reported that the livepatch self-tests were failing, specifically
a case in which the consistency model ensures that a current executing
function is not allowed to be patched, "TEST: busy target module".
Recent renovations of stack_trace_save_tsk_reliable() left it returning
only an -ERRNO success indication in some configuration combinations:
klp_check_stack()
ret = stack_trace_save_tsk_reliable()
#ifdef CONFIG_ARCH_STACKWALK && CONFIG_HAVE_RELIABLE_STACKTRACE
stack_trace_save_tsk_reliable()
ret = arch_stack_walk_reliable()
return 0
return -EINVAL
...
return ret;
...
if (ret < 0)
/* stack_trace_save_tsk_reliable error */
nr_entries = ret; << 0
Previously (and currently for !CONFIG_ARCH_STACKWALK &&
CONFIG_HAVE_RELIABLE_STACKTRACE) stack_trace_save_tsk_reliable() returned
the number of entries that it consumed in the passed storage array.
In the case of the above config and trace, be sure to return the
stacktrace_cookie.len on stack_trace_save_tsk_reliable() success.
Fixes: 25e39e32b0a3f ("livepatch: Simplify stack trace retrieval")
Reported-by: Miroslav Benes <[email protected]>
Signed-off-by: Joe Lawrence <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Reviewed-by: Kamalesh Babulal <[email protected]>
Acked-by: Josh Poimboeuf <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Link: https://lkml.kernel.org/r/[email protected]
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All architectures which support stacktrace carry duplicated code and
do the stack storage and filtering at the architecture side.
Provide a consolidated interface with a callback function for consuming the
stack entries provided by the architecture specific stack walker. This
removes lots of duplicated code and allows to implement better filtering
than 'skip number of entries' in the future without touching any
architecture specific code.
Signed-off-by: Thomas Gleixner <[email protected]>
Reviewed-by: Josh Poimboeuf <[email protected]>
Cc: Andy Lutomirski <[email protected]>
Cc: [email protected]
Cc: Steven Rostedt <[email protected]>
Cc: Alexander Potapenko <[email protected]>
Cc: Alexey Dobriyan <[email protected]>
Cc: Andrew Morton <[email protected]>
Cc: Christoph Lameter <[email protected]>
Cc: Pekka Enberg <[email protected]>
Cc: [email protected]
Cc: David Rientjes <[email protected]>
Cc: Catalin Marinas <[email protected]>
Cc: Dmitry Vyukov <[email protected]>
Cc: Andrey Ryabinin <[email protected]>
Cc: [email protected]
Cc: Mike Rapoport <[email protected]>
Cc: Akinobu Mita <[email protected]>
Cc: Christoph Hellwig <[email protected]>
Cc: [email protected]
Cc: Robin Murphy <[email protected]>
Cc: Marek Szyprowski <[email protected]>
Cc: Johannes Thumshirn <[email protected]>
Cc: David Sterba <[email protected]>
Cc: Chris Mason <[email protected]>
Cc: Josef Bacik <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: Mike Snitzer <[email protected]>
Cc: Alasdair Kergon <[email protected]>
Cc: Daniel Vetter <[email protected]>
Cc: [email protected]
Cc: Joonas Lahtinen <[email protected]>
Cc: Maarten Lankhorst <[email protected]>
Cc: [email protected]
Cc: David Airlie <[email protected]>
Cc: Jani Nikula <[email protected]>
Cc: Rodrigo Vivi <[email protected]>
Cc: Tom Zanussi <[email protected]>
Cc: Miroslav Benes <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]
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No more users of the struct stack_trace based interfaces. Remove them.
Remove the macro stubs for !CONFIG_STACKTRACE as well as they are pointless
because the storage on the call sites is conditional on CONFIG_STACKTRACE
already. No point to be 'smart'.
Signed-off-by: Thomas Gleixner <[email protected]>
Reviewed-by: Josh Poimboeuf <[email protected]>
Cc: Andy Lutomirski <[email protected]>
Cc: Steven Rostedt <[email protected]>
Cc: Alexander Potapenko <[email protected]>
Cc: Alexey Dobriyan <[email protected]>
Cc: Andrew Morton <[email protected]>
Cc: Christoph Lameter <[email protected]>
Cc: Pekka Enberg <[email protected]>
Cc: [email protected]
Cc: David Rientjes <[email protected]>
Cc: Catalin Marinas <[email protected]>
Cc: Dmitry Vyukov <[email protected]>
Cc: Andrey Ryabinin <[email protected]>
Cc: [email protected]
Cc: Mike Rapoport <[email protected]>
Cc: Akinobu Mita <[email protected]>
Cc: Christoph Hellwig <[email protected]>
Cc: [email protected]
Cc: Robin Murphy <[email protected]>
Cc: Marek Szyprowski <[email protected]>
Cc: Johannes Thumshirn <[email protected]>
Cc: David Sterba <[email protected]>
Cc: Chris Mason <[email protected]>
Cc: Josef Bacik <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: Mike Snitzer <[email protected]>
Cc: Alasdair Kergon <[email protected]>
Cc: Daniel Vetter <[email protected]>
Cc: [email protected]
Cc: Joonas Lahtinen <[email protected]>
Cc: Maarten Lankhorst <[email protected]>
Cc: [email protected]
Cc: David Airlie <[email protected]>
Cc: Jani Nikula <[email protected]>
Cc: Rodrigo Vivi <[email protected]>
Cc: Tom Zanussi <[email protected]>
Cc: Miroslav Benes <[email protected]>
Cc: [email protected]
Link: https://lkml.kernel.org/r/[email protected]
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All operations with stack traces are based on struct stack_trace. That's a
horrible construct as the struct is a kitchen sink for input and
output. Quite some usage sites embed it into their own data structures
which creates weird indirections.
There is absolutely no point in doing so. For all use cases a storage array
and the number of valid stack trace entries in the array is sufficient.
Provide helper functions which avoid the struct stack_trace indirection so
the usage sites can be cleaned up.
Signed-off-by: Thomas Gleixner <[email protected]>
Reviewed-by: Josh Poimboeuf <[email protected]>
Cc: Andy Lutomirski <[email protected]>
Cc: Steven Rostedt <[email protected]>
Cc: Alexander Potapenko <[email protected]>
Cc: Alexey Dobriyan <[email protected]>
Cc: Andrew Morton <[email protected]>
Cc: Christoph Lameter <[email protected]>
Cc: Pekka Enberg <[email protected]>
Cc: [email protected]
Cc: David Rientjes <[email protected]>
Cc: Catalin Marinas <[email protected]>
Cc: Dmitry Vyukov <[email protected]>
Cc: Andrey Ryabinin <[email protected]>
Cc: [email protected]
Cc: Mike Rapoport <[email protected]>
Cc: Akinobu Mita <[email protected]>
Cc: Christoph Hellwig <[email protected]>
Cc: [email protected]
Cc: Robin Murphy <[email protected]>
Cc: Marek Szyprowski <[email protected]>
Cc: Johannes Thumshirn <[email protected]>
Cc: David Sterba <[email protected]>
Cc: Chris Mason <[email protected]>
Cc: Josef Bacik <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: Mike Snitzer <[email protected]>
Cc: Alasdair Kergon <[email protected]>
Cc: Daniel Vetter <[email protected]>
Cc: [email protected]
Cc: Joonas Lahtinen <[email protected]>
Cc: Maarten Lankhorst <[email protected]>
Cc: [email protected]
Cc: David Airlie <[email protected]>
Cc: Jani Nikula <[email protected]>
Cc: Rodrigo Vivi <[email protected]>
Cc: Tom Zanussi <[email protected]>
Cc: Miroslav Benes <[email protected]>
Cc: [email protected]
Link: https://lkml.kernel.org/r/[email protected]
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For live patching and possibly other use cases, a stack trace is only
useful if it can be assured that it's completely reliable. Add a new
save_stack_trace_tsk_reliable() function to achieve that.
Note that if the target task isn't the current task, and the target task
is allowed to run, then it could be writing the stack while the unwinder
is reading it, resulting in possible corruption. So the caller of
save_stack_trace_tsk_reliable() must ensure that the task is either
'current' or inactive.
save_stack_trace_tsk_reliable() relies on the x86 unwinder's detection
of pt_regs on the stack. If the pt_regs are not user-mode registers
from a syscall, then they indicate an in-kernel interrupt or exception
(e.g. preemption or a page fault), in which case the stack is considered
unreliable due to the nature of frame pointers.
It also relies on the x86 unwinder's detection of other issues, such as:
- corrupted stack data
- stack grows the wrong way
- stack walk doesn't reach the bottom
- user didn't provide a large enough entries array
Such issues are reported by checking unwind_error() and !unwind_done().
Also add CONFIG_HAVE_RELIABLE_STACKTRACE so arch-independent code can
determine at build time whether the function is implemented.
Signed-off-by: Josh Poimboeuf <[email protected]>
Reviewed-by: Miroslav Benes <[email protected]>
Acked-by: Ingo Molnar <[email protected]> # for the x86 changes
Signed-off-by: Jiri Kosina <[email protected]>
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Since KERN_CONT became meaningful again, lockdep stack traces have had
annoying extra newlines, like this:
[ 5.561122] -> #1 (B){+.+...}:
[ 5.561528]
[ 5.561532] [<ffffffff810d8873>] lock_acquire+0xc3/0x210
[ 5.562178]
[ 5.562181] [<ffffffff816f6414>] mutex_lock_nested+0x74/0x6d0
[ 5.562861]
[ 5.562880] [<ffffffffa01aa3c3>] init_btrfs_fs+0x21/0x196 [btrfs]
[ 5.563717]
[ 5.563721] [<ffffffff81000472>] do_one_initcall+0x52/0x1b0
[ 5.564554]
[ 5.564559] [<ffffffff811a3af6>] do_init_module+0x5f/0x209
[ 5.565357]
[ 5.565361] [<ffffffff81122f4d>] load_module+0x218d/0x2b80
[ 5.566020]
[ 5.566021] [<ffffffff81123beb>] SyS_finit_module+0xeb/0x120
[ 5.566694]
[ 5.566696] [<ffffffff816fd241>] entry_SYSCALL_64_fastpath+0x1f/0xc2
That's happening because each printk() call now gets printed on its own
line, and we do a separate call to print the spaces before the symbol.
Fix it by doing the printk() directly instead of using the
print_ip_sym() helper.
Additionally, the symbol address isn't very helpful, so let's get rid of
that, too. The final result looks like this:
[ 5.194518] -> #1 (B){+.+...}:
[ 5.195002] lock_acquire+0xc3/0x210
[ 5.195439] mutex_lock_nested+0x74/0x6d0
[ 5.196491] do_one_initcall+0x52/0x1b0
[ 5.196939] do_init_module+0x5f/0x209
[ 5.197355] load_module+0x218d/0x2b80
[ 5.197792] SyS_finit_module+0xeb/0x120
[ 5.198251] entry_SYSCALL_64_fastpath+0x1f/0xc2
Suggested-by: Linus Torvalds <[email protected]>
Signed-off-by: Omar Sandoval <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: [email protected]
Fixes: 4bcc595ccd80 ("printk: reinstate KERN_CONT for printing continuation lines")
Link: http://lkml.kernel.org/r/43b4e114724b2bdb0308fa86cb33aa07d3d67fad.1486510315.git.osandov@fb.com
Signed-off-by: Ingo Molnar <[email protected]>
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Current stacktrace only have the function for console output. page_owner
that will be introduced in following patch needs to print the output of
stacktrace into the buffer for our own output format so so new function,
snprint_stack_trace(), is needed.
Signed-off-by: Joonsoo Kim <[email protected]>
Cc: Mel Gorman <[email protected]>
Cc: Johannes Weiner <[email protected]>
Cc: Minchan Kim <[email protected]>
Cc: Dave Hansen <[email protected]>
Cc: Michal Nazarewicz <[email protected]>
Cc: Jungsoo Son <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Joonsoo Kim <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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The changed files were only including linux/module.h for the
EXPORT_SYMBOL infrastructure, and nothing else. Revector them
onto the isolated export header for faster compile times.
Nothing to see here but a whole lot of instances of:
-#include <linux/module.h>
+#include <linux/export.h>
This commit is only changing the kernel dir; next targets
will probably be mm, fs, the arch dirs, etc.
Signed-off-by: Paul Gortmaker <[email protected]>
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Add weak symbol of save_stack_trace_regs() as same as
save_stack_trace_tsk() since that is not implemented
except x86 yet.
Signed-off-by: Masami Hiramatsu <[email protected]>
Cc: Frederic Weisbecker <[email protected]>
Cc: [email protected]
Cc: Peter Zijlstra <[email protected]>
Cc: Namhyung Kim <[email protected]>
Link: http://lkml.kernel.org/r/20110608070927.17777.37895.stgit@fedora15
Signed-off-by: Steven Rostedt <[email protected]>
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Impact: build fix
Some architectures have not implemented save_stack_trace_tsk() yet:
fs/built-in.o: In function `proc_pid_stack':
base.c:(.text+0x3f140): undefined reference to `save_stack_trace_tsk'
So warn about that if the facility is used.
Signed-off-by: Ingo Molnar <[email protected]>
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fix:
ERROR: "print_stack_trace" [kernel/backtracetest.ko] undefined!
ERROR: "save_stack_trace" [kernel/backtracetest.ko] undefined!
Signed-off-by: Ingo Molnar <[email protected]>
and fix:
Building modules, stage 2.
MODPOST 376 modules
ERROR: "print_stack_trace" [kernel/backtracetest.ko] undefined!
make[1]: *** [__modpost] Error 1
Signed-off-by: Ingo Molnar <[email protected]>
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- shorter code and better atomicity with regards to printk().
(It's been tested with the backtrace self-test code on i386 and x86_64.)
Cc: Arjan van de Ven <[email protected]>
Signed-off-by: Vegard Nossum <[email protected]>
Signed-off-by: Ingo Molnar <[email protected]>
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This patch makes the stacktrace printout code \warn when the entries
pointer is unset rather than crashing when trying to access it in an
attempt to make it a bit more robust.
I was saving a stacktrace into an skb and forgot to copy it across skb
copies... I have since fixed the code, but it would have been easier
had the kernel not crashed in an interrupt.
Signed-off-by: Johannes Berg <[email protected]>
Signed-off-by: Ingo Molnar <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
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Framework to generate and save stacktraces quickly, without printing anything
to the console.
Signed-off-by: Ingo Molnar <[email protected]>
Signed-off-by: Arjan van de Ven <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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