Messages in this thread Patch in this message | | | Date | Sun, 19 May 2019 02:46:25 -0700 | From | tip-bot for Joe Lawrence <> | Subject | [tip:core/urgent] stacktrace: Unbreak stack_trace_save_tsk_reliable() |
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Commit-ID: 7eaf51a2e094229b75cc0c315f1cbbe2f3960058 Gitweb: https://git.kernel.org/tip/7eaf51a2e094229b75cc0c315f1cbbe2f3960058 Author: Joe Lawrence <joe.lawrence@redhat.com> AuthorDate: Fri, 17 May 2019 14:51:17 -0400 Committer: Thomas Gleixner <tglx@linutronix.de> CommitDate: Sun, 19 May 2019 11:43:22 +0200
stacktrace: Unbreak stack_trace_save_tsk_reliable()
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 <mbenes@suse.cz> Signed-off-by: Joe Lawrence <joe.lawrence@redhat.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Kamalesh Babulal <kamalesh@linux.vnet.ibm.com> Acked-by: Josh Poimboeuf <jpoimboe@redhat.com> 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
--- kernel/stacktrace.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/stacktrace.c b/kernel/stacktrace.c index 27bafc1e271e..90d3e0bf0302 100644 --- a/kernel/stacktrace.c +++ b/kernel/stacktrace.c @@ -206,7 +206,7 @@ int stack_trace_save_tsk_reliable(struct task_struct *tsk, unsigned long *store, ret = arch_stack_walk_reliable(consume_entry, &c, tsk); put_task_stack(tsk); - return ret; + return ret ? ret : c.len; } #endif
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