user/sven/linux.git/kernel/stacktrace.c, branch v5.8.8

stacktrace: Get rid of unneeded '!!' pattern

2019-11-11T09:30:59Z

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 Signed-off-by: Jiri Slaby Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Link: https://lkml.kernel.org/r/20191111092647.27419-1-jslaby@suse.cz Signed-off-by: Ingo Molnar

stacktrace: Don't skip first entry on noncurrent tasks

2019-11-04T20:19:25Z

When doing cat /proc//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 Signed-off-by: Thomas Gleixner Tested-by: Michal Suchanek Acked-by: Josh Poimboeuf Link: https://lkml.kernel.org/r/20191030072545.19462-1-jslaby@suse.cz

stacktrace: Constify 'entries' arguments

2019-07-25T13:43:26Z

Make it clear to humans and to the compiler that the stack trace ('entries') arguments are not modified. Signed-off-by: Bart Van Assche Signed-off-by: Peter Zijlstra (Intel) Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: Waiman Long Cc: Will Deacon Link: https://lkml.kernel.org/r/20190722182443.216015-3-bvanassche@acm.org Signed-off-by: Ingo Molnar

stacktrace: Force USER_DS for stack_trace_save_user()

2019-07-18T14:47:24Z

When walking userspace stacks, USER_DS needs to be set, otherwise access_ok() will not function as expected. Reported-by: Vegard Nossum Reported-by: Eiichi Tsukata Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: Thomas Gleixner Tested-by: Vegard Nossum Reviewed-by: Joel Fernandes (Google) Link: https://lkml.kernel.org/r/20190718085754.GM3402@hirez.programming.kicks-ass.net

Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/livepatching/livepatching

2019-07-11T22:30:05Z

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

stacktrace: Use PF_KTHREAD to check for kernel threads

2019-07-03T07:04:06Z

!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 Acked-by: Mark Rutland Cc: Josh Poimboeuf Cc: Peter Zijlstra Cc: Steven Rostedt Link: https://lkml.kernel.org/r/alpine.DEB.2.21.1907021750100.1802@nanos.tec.linutronix.de

stacktrace: Remove weak version of save_stack_trace_tsk_reliable()

2019-06-20T13:43:31Z

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 Acked-by: Josh Poimboeuf Reviewed-by: Thomas Gleixner Reviewed-by: Kamalesh Babulal Signed-off-by: Petr Mladek

Merge branch 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2019-06-02T18:04:42Z

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()

treewide: Add SPDX license identifier for missed files

2019-05-21T08:50:45Z

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 Signed-off-by: Greg Kroah-Hartman

stacktrace: Unbreak stack_trace_save_tsk_reliable()

2019-05-19T09:43:22Z

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 Signed-off-by: Joe Lawrence Signed-off-by: Thomas Gleixner Reviewed-by: Kamalesh Babulal Acked-by: Josh Poimboeuf Cc: live-patching@vger.kernel.org Cc: jikos@kernel.org Cc: pmladek@suse.com Link: https://lkml.kernel.org/r/20190517185117.24642-1-joe.lawrence@redhat.com