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authorJoe Lawrence <joe.lawrence@redhat.com>2019-05-17 18:51:17 (GMT)
committerThomas Gleixner <tglx@linutronix.de>2019-05-19 09:43:22 (GMT)
commit7eaf51a2e094229b75cc0c315f1cbbe2f3960058 (patch)
treeb62c0d6dc023c4b01b58070c4a511fecc80dd4f7 /kernel/stacktrace.c
parent8ea58f1e8b11cca3087b294779bf5959bf89cc10 (diff)
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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
Diffstat (limited to 'kernel/stacktrace.c')
-rw-r--r--kernel/stacktrace.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/kernel/stacktrace.c b/kernel/stacktrace.c
index 27bafc1..90d3e0b 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