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authorLinus Torvalds <torvalds@linux-foundation.org>2020-05-17 12:20:14 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2020-05-17 12:20:14 -0700
commitef0d5b9102c4614c45e04ede10d04e572a165ca8 (patch)
tree0034d5416d64629affcb2082316d044dbff46324
parent43567139f5f3808cda4f61c956576f8a4f2232cb (diff)
parent71c95825289f585014fe9741b051d32a7a916680 (diff)
downloadlinux-ef0d5b9102c4614c45e04ede10d04e572a165ca8.tar.gz
Merge tag 'objtool-urgent-2020-05-17' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 stack unwinding fix from Thomas Gleixner: "A single bugfix for the ORC unwinder to ensure that the error flag which tells the unwinding code whether a stack trace can be trusted or not is always set correctly. This was messed up by a couple of changes in the recent past" * tag 'objtool-urgent-2020-05-17' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/unwind/orc: Fix error handling in __unwind_start()
-rw-r--r--arch/x86/kernel/unwind_orc.c16
1 files changed, 9 insertions, 7 deletions
diff --git a/arch/x86/kernel/unwind_orc.c b/arch/x86/kernel/unwind_orc.c
index 5b0bd8581fe6..fa79e4227d3d 100644
--- a/arch/x86/kernel/unwind_orc.c
+++ b/arch/x86/kernel/unwind_orc.c
@@ -617,23 +617,23 @@ EXPORT_SYMBOL_GPL(unwind_next_frame);
void __unwind_start(struct unwind_state *state, struct task_struct *task,
struct pt_regs *regs, unsigned long *first_frame)
{
- if (!orc_init)
- goto done;
-
memset(state, 0, sizeof(*state));
state->task = task;
+ if (!orc_init)
+ goto err;
+
/*
* Refuse to unwind the stack of a task while it's executing on another
* CPU. This check is racy, but that's ok: the unwinder has other
* checks to prevent it from going off the rails.
*/
if (task_on_another_cpu(task))
- goto done;
+ goto err;
if (regs) {
if (user_mode(regs))
- goto done;
+ goto the_end;
state->ip = regs->ip;
state->sp = regs->sp;
@@ -666,6 +666,7 @@ void __unwind_start(struct unwind_state *state, struct task_struct *task,
* generate some kind of backtrace if this happens.
*/
void *next_page = (void *)PAGE_ALIGN((unsigned long)state->sp);
+ state->error = true;
if (get_stack_info(next_page, state->task, &state->stack_info,
&state->stack_mask))
return;
@@ -691,8 +692,9 @@ void __unwind_start(struct unwind_state *state, struct task_struct *task,
return;
-done:
+err:
+ state->error = true;
+the_end:
state->stack_info.type = STACK_TYPE_UNKNOWN;
- return;
}
EXPORT_SYMBOL_GPL(__unwind_start);