arch/loongarch/kernel/stacktrace.c | 3 ++- arch/loongarch/kernel/unwind.c | 1 + arch/loongarch/kernel/unwind_prologue.c | 4 +++- 3 files changed, 6 insertions(+), 2 deletions(-)
We can see the following messages with CONFIG_PROVE_LOCKING=y on
LoongArch:
BUG: MAX_STACK_TRACE_ENTRIES too low!
turning off the locking correctness validator.
This is because stack_trace_save() returns a big value after call
arch_stack_walk(), here is the call trace:
save_trace()
stack_trace_save()
arch_stack_walk()
stack_trace_consume_entry()
arch_stack_walk() should return immediately if unwind_next_frame()
failed, no need to do the useless loops to increase the value of
c->len in stack_trace_consume_entry(), then we can fix the above
problem.
Reported-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/all/8a44ad71-68d2-4926-892f-72bfc7a67e2a@roeck-us.net/
Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
---
arch/loongarch/kernel/stacktrace.c | 3 ++-
arch/loongarch/kernel/unwind.c | 1 +
arch/loongarch/kernel/unwind_prologue.c | 4 +++-
3 files changed, 6 insertions(+), 2 deletions(-)
diff --git a/arch/loongarch/kernel/stacktrace.c b/arch/loongarch/kernel/stacktrace.c
index 3a690f9..7c15ba5 100644
--- a/arch/loongarch/kernel/stacktrace.c
+++ b/arch/loongarch/kernel/stacktrace.c
@@ -30,7 +30,8 @@ void arch_stack_walk(stack_trace_consume_fn consume_entry, void *cookie,
regs->regs[1] = 0;
for (unwind_start(&state, task, regs);
- !unwind_done(&state); unwind_next_frame(&state)) {
+ !unwind_done(&state) && !unwind_error(&state);
+ unwind_next_frame(&state)) {
addr = unwind_get_return_address(&state);
if (!addr || !consume_entry(cookie, addr))
break;
diff --git a/arch/loongarch/kernel/unwind.c b/arch/loongarch/kernel/unwind.c
index a463d69..ba324ba 100644
--- a/arch/loongarch/kernel/unwind.c
+++ b/arch/loongarch/kernel/unwind.c
@@ -28,5 +28,6 @@ bool default_next_frame(struct unwind_state *state)
} while (!get_stack_info(state->sp, state->task, info));
+ state->error = true;
return false;
}
diff --git a/arch/loongarch/kernel/unwind_prologue.c b/arch/loongarch/kernel/unwind_prologue.c
index 9095fde..55afc27 100644
--- a/arch/loongarch/kernel/unwind_prologue.c
+++ b/arch/loongarch/kernel/unwind_prologue.c
@@ -211,7 +211,7 @@ static bool next_frame(struct unwind_state *state)
pc = regs->csr_era;
if (user_mode(regs) || !__kernel_text_address(pc))
- return false;
+ goto out;
state->first = true;
state->pc = pc;
@@ -226,6 +226,8 @@ static bool next_frame(struct unwind_state *state)
} while (!get_stack_info(state->sp, state->task, info));
+out:
+ state->error = true;
return false;
}
--
2.1.0On Tue, 2023-03-21 at 14:29 +0800, Tiezhu Yang wrote:
> We can see the following messages with CONFIG_PROVE_LOCKING=y on
> LoongArch:
>
> BUG: MAX_STACK_TRACE_ENTRIES too low!
> turning off the locking correctness validator.
>
> This is because stack_trace_save() returns a big value after call
> arch_stack_walk(), here is the call trace:
>
> save_trace()
> stack_trace_save()
> arch_stack_walk()
> stack_trace_consume_entry()
>
> arch_stack_walk() should return immediately if unwind_next_frame()
> failed, no need to do the useless loops to increase the value of
> c->len in stack_trace_consume_entry(), then we can fix the above
> problem.
>
> Reported-by: Guenter Roeck <linux@roeck-us.net>
> Link: https://lore.kernel.org/all/8a44ad71-68d2-4926-892f-72bfc7a67e2a@roeck-us.net/
> Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
The fix makes sense, but I'm asking the same question again (sorry if
it's noisy): should we Cc stable@vger.kernel.org and/or make a PR for
6.3?
To me a bug fixes should be backported into all stable branches affected
by the bug, unless there is some serious difficulty. As 6.3 release
will work on launched 3A5000 boards out-of-box, people may want to stop
staying on the leading edge and use a LTS/stable release series. We
can't just say (or behave like) "we don't backport, please use latest
mainline" IMO :).
> ---
> arch/loongarch/kernel/stacktrace.c | 3 ++-
> arch/loongarch/kernel/unwind.c | 1 +
> arch/loongarch/kernel/unwind_prologue.c | 4 +++-
> 3 files changed, 6 insertions(+), 2 deletions(-)
>
> diff --git a/arch/loongarch/kernel/stacktrace.c b/arch/loongarch/kernel/stacktrace.c
> index 3a690f9..7c15ba5 100644
> --- a/arch/loongarch/kernel/stacktrace.c
> +++ b/arch/loongarch/kernel/stacktrace.c
> @@ -30,7 +30,8 @@ void arch_stack_walk(stack_trace_consume_fn consume_entry, void *cookie,
>
> regs->regs[1] = 0;
> for (unwind_start(&state, task, regs);
> - !unwind_done(&state); unwind_next_frame(&state)) {
> + !unwind_done(&state) && !unwind_error(&state);
> + unwind_next_frame(&state)) {
> addr = unwind_get_return_address(&state);
> if (!addr || !consume_entry(cookie, addr))
> break;
> diff --git a/arch/loongarch/kernel/unwind.c b/arch/loongarch/kernel/unwind.c
> index a463d69..ba324ba 100644
> --- a/arch/loongarch/kernel/unwind.c
> +++ b/arch/loongarch/kernel/unwind.c
> @@ -28,5 +28,6 @@ bool default_next_frame(struct unwind_state *state)
>
> } while (!get_stack_info(state->sp, state->task, info));
>
> + state->error = true;
> return false;
> }
> diff --git a/arch/loongarch/kernel/unwind_prologue.c b/arch/loongarch/kernel/unwind_prologue.c
> index 9095fde..55afc27 100644
> --- a/arch/loongarch/kernel/unwind_prologue.c
> +++ b/arch/loongarch/kernel/unwind_prologue.c
> @@ -211,7 +211,7 @@ static bool next_frame(struct unwind_state *state)
> pc = regs->csr_era;
>
> if (user_mode(regs) || !__kernel_text_address(pc))
> - return false;
> + goto out;
>
> state->first = true;
> state->pc = pc;
> @@ -226,6 +226,8 @@ static bool next_frame(struct unwind_state *state)
>
> } while (!get_stack_info(state->sp, state->task, info));
>
> +out:
> + state->error = true;
> return false;
> }
>
--
Xi Ruoyao <xry111@xry111.site>
School of Aerospace Science and Technology, Xidian University
On Tue, Mar 21, 2023 at 08:35:34PM +0800, Xi Ruoyao wrote: > On Tue, 2023-03-21 at 14:29 +0800, Tiezhu Yang wrote: > > We can see the following messages with CONFIG_PROVE_LOCKING=y on > > LoongArch: > > > > BUG: MAX_STACK_TRACE_ENTRIES too low! > > turning off the locking correctness validator. > > > > This is because stack_trace_save() returns a big value after call > > arch_stack_walk(), here is the call trace: > > > > save_trace() > > stack_trace_save() > > arch_stack_walk() > > stack_trace_consume_entry() > > > > arch_stack_walk() should return immediately if unwind_next_frame() > > failed, no need to do the useless loops to increase the value of > > c->len in stack_trace_consume_entry(), then we can fix the above > > problem. > > > > Reported-by: Guenter Roeck <linux@roeck-us.net> > > Link: https://lore.kernel.org/all/8a44ad71-68d2-4926-892f-72bfc7a67e2a@roeck-us.net/ > > Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn> > > The fix makes sense, but I'm asking the same question again (sorry if > it's noisy): should we Cc stable@vger.kernel.org and/or make a PR for > 6.3? > > To me a bug fixes should be backported into all stable branches affected > by the bug, unless there is some serious difficulty. As 6.3 release > will work on launched 3A5000 boards out-of-box, people may want to stop > staying on the leading edge and use a LTS/stable release series. We > can't just say (or behave like) "we don't backport, please use latest > mainline" IMO :). It is a bug fix, isn't it ? It should be backported to v6.1+. Otherwise, if your policy is to not backport bug fixes, I might as well stop testing loongarch on all but the most recent kernel branch. Let me know if this is what you want. If so, I think you should let all other regression testers know that they should only test loongarch on mainline and possibly on linux-next. Thanks, Guenter
On Tue, Mar 21, 2023 at 10:25 PM Guenter Roeck <linux@roeck-us.net> wrote: > > On Tue, Mar 21, 2023 at 08:35:34PM +0800, Xi Ruoyao wrote: > > On Tue, 2023-03-21 at 14:29 +0800, Tiezhu Yang wrote: > > > We can see the following messages with CONFIG_PROVE_LOCKING=y on > > > LoongArch: > > > > > > BUG: MAX_STACK_TRACE_ENTRIES too low! > > > turning off the locking correctness validator. > > > > > > This is because stack_trace_save() returns a big value after call > > > arch_stack_walk(), here is the call trace: > > > > > > save_trace() > > > stack_trace_save() > > > arch_stack_walk() > > > stack_trace_consume_entry() > > > > > > arch_stack_walk() should return immediately if unwind_next_frame() > > > failed, no need to do the useless loops to increase the value of > > > c->len in stack_trace_consume_entry(), then we can fix the above > > > problem. > > > > > > Reported-by: Guenter Roeck <linux@roeck-us.net> > > > Link: https://lore.kernel.org/all/8a44ad71-68d2-4926-892f-72bfc7a67e2a@roeck-us.net/ > > > Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn> > > > > The fix makes sense, but I'm asking the same question again (sorry if > > it's noisy): should we Cc stable@vger.kernel.org and/or make a PR for > > 6.3? > > > > To me a bug fixes should be backported into all stable branches affected > > by the bug, unless there is some serious difficulty. As 6.3 release > > will work on launched 3A5000 boards out-of-box, people may want to stop > > staying on the leading edge and use a LTS/stable release series. We > > can't just say (or behave like) "we don't backport, please use latest > > mainline" IMO :). > > It is a bug fix, isn't it ? It should be backported to v6.1+. Otherwise, > if your policy is to not backport bug fixes, I might as well stop testing > loongarch on all but the most recent kernel branch. Let me know if this is > what you want. If so, I think you should let all other regression testers > know that they should only test loongarch on mainline and possibly on > linux-next. This is of course a bug fix, but should Tiezhu resend this patch? Or just replying to this message with CC stable@vger.kernel.org is enough? Huacai > > Thanks, > Guenter
On Wed, Mar 22, 2023 at 08:50:07AM +0800, Huacai Chen wrote: > On Tue, Mar 21, 2023 at 10:25 PM Guenter Roeck <linux@roeck-us.net> wrote: > > > > On Tue, Mar 21, 2023 at 08:35:34PM +0800, Xi Ruoyao wrote: > > > On Tue, 2023-03-21 at 14:29 +0800, Tiezhu Yang wrote: > > > > We can see the following messages with CONFIG_PROVE_LOCKING=y on > > > > LoongArch: > > > > > > > > BUG: MAX_STACK_TRACE_ENTRIES too low! > > > > turning off the locking correctness validator. > > > > > > > > This is because stack_trace_save() returns a big value after call > > > > arch_stack_walk(), here is the call trace: > > > > > > > > save_trace() > > > > stack_trace_save() > > > > arch_stack_walk() > > > > stack_trace_consume_entry() > > > > > > > > arch_stack_walk() should return immediately if unwind_next_frame() > > > > failed, no need to do the useless loops to increase the value of > > > > c->len in stack_trace_consume_entry(), then we can fix the above > > > > problem. > > > > > > > > Reported-by: Guenter Roeck <linux@roeck-us.net> > > > > Link: https://lore.kernel.org/all/8a44ad71-68d2-4926-892f-72bfc7a67e2a@roeck-us.net/ > > > > Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn> > > > > > > The fix makes sense, but I'm asking the same question again (sorry if > > > it's noisy): should we Cc stable@vger.kernel.org and/or make a PR for > > > 6.3? > > > > > > To me a bug fixes should be backported into all stable branches affected > > > by the bug, unless there is some serious difficulty. As 6.3 release > > > will work on launched 3A5000 boards out-of-box, people may want to stop > > > staying on the leading edge and use a LTS/stable release series. We > > > can't just say (or behave like) "we don't backport, please use latest > > > mainline" IMO :). > > > > It is a bug fix, isn't it ? It should be backported to v6.1+. Otherwise, > > if your policy is to not backport bug fixes, I might as well stop testing > > loongarch on all but the most recent kernel branch. Let me know if this is > > what you want. If so, I think you should let all other regression testers > > know that they should only test loongarch on mainline and possibly on > > linux-next. > This is of course a bug fix, but should Tiezhu resend this patch? Or > just replying to this message with CC stable@vger.kernel.org is > enough? > Normally the maintainer, before sending a pull request to Linus, would add "Cc: stable@vger.kernel.org" to the patch. Actually sending the patch to the stable@ mailing list is only necessary if it was applied to the upstream kernel without Cc: stable@ in the commit message. Guenter
OK, thanks. Huacai On Wed, Mar 22, 2023 at 10:20 AM Guenter Roeck <linux@roeck-us.net> wrote: > > On Wed, Mar 22, 2023 at 08:50:07AM +0800, Huacai Chen wrote: > > On Tue, Mar 21, 2023 at 10:25 PM Guenter Roeck <linux@roeck-us.net> wrote: > > > > > > On Tue, Mar 21, 2023 at 08:35:34PM +0800, Xi Ruoyao wrote: > > > > On Tue, 2023-03-21 at 14:29 +0800, Tiezhu Yang wrote: > > > > > We can see the following messages with CONFIG_PROVE_LOCKING=y on > > > > > LoongArch: > > > > > > > > > > BUG: MAX_STACK_TRACE_ENTRIES too low! > > > > > turning off the locking correctness validator. > > > > > > > > > > This is because stack_trace_save() returns a big value after call > > > > > arch_stack_walk(), here is the call trace: > > > > > > > > > > save_trace() > > > > > stack_trace_save() > > > > > arch_stack_walk() > > > > > stack_trace_consume_entry() > > > > > > > > > > arch_stack_walk() should return immediately if unwind_next_frame() > > > > > failed, no need to do the useless loops to increase the value of > > > > > c->len in stack_trace_consume_entry(), then we can fix the above > > > > > problem. > > > > > > > > > > Reported-by: Guenter Roeck <linux@roeck-us.net> > > > > > Link: https://lore.kernel.org/all/8a44ad71-68d2-4926-892f-72bfc7a67e2a@roeck-us.net/ > > > > > Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn> > > > > > > > > The fix makes sense, but I'm asking the same question again (sorry if > > > > it's noisy): should we Cc stable@vger.kernel.org and/or make a PR for > > > > 6.3? > > > > > > > > To me a bug fixes should be backported into all stable branches affected > > > > by the bug, unless there is some serious difficulty. As 6.3 release > > > > will work on launched 3A5000 boards out-of-box, people may want to stop > > > > staying on the leading edge and use a LTS/stable release series. We > > > > can't just say (or behave like) "we don't backport, please use latest > > > > mainline" IMO :). > > > > > > It is a bug fix, isn't it ? It should be backported to v6.1+. Otherwise, > > > if your policy is to not backport bug fixes, I might as well stop testing > > > loongarch on all but the most recent kernel branch. Let me know if this is > > > what you want. If so, I think you should let all other regression testers > > > know that they should only test loongarch on mainline and possibly on > > > linux-next. > > This is of course a bug fix, but should Tiezhu resend this patch? Or > > just replying to this message with CC stable@vger.kernel.org is > > enough? > > > > Normally the maintainer, before sending a pull request to Linus, would add > "Cc: stable@vger.kernel.org" to the patch. Actually sending the patch to > the stable@ mailing list is only necessary if it was applied to the > upstream kernel without Cc: stable@ in the commit message. > > Guenter
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