lkml.org 
[lkml]   [2020]   [May]   [17]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
Subject[GIT pull] objtool/urgent for v5.7-rc6
Linus,

please pull the latest objtool/urgent branch from:

git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git objtool-urgent-2020-05-17

up to: 71c95825289f: x86/unwind/orc: Fix error handling in __unwind_start()


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.

Thanks,

tglx

------------------>
Josh Poimboeuf (1):
x86/unwind/orc: Fix error handling in __unwind_start()


arch/x86/kernel/unwind_orc.c | 16 +++++++++-------
1 file 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);
\
 
 \ /
  Last update: 2020-05-17 12:05    [W:0.043 / U:0.964 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site