Commit-ID: 7eaf51a2e094229b75cc0c315f1cbbe2f3960058
Gitweb: https://git.kernel.org/tip/7eaf51a2e094229b75cc0c315f1cbbe2f3960058
Author: Joe Lawrence <[email protected]>
AuthorDate: Fri, 17 May 2019 14:51:17 -0400
Committer: Thomas Gleixner <[email protected]>
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 <[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]
---
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
