* Re: [syzbot] [bcachefs?] [rcu?] BUG: unable to handle kernel NULL pointer dereference in rcu_core (3)
[not found] <20250609052925.971-1-hdanton@sina.com>
@ 2025-06-09 6:01 ` syzbot
0 siblings, 0 replies; 9+ messages in thread
From: syzbot @ 2025-06-09 6:01 UTC (permalink / raw)
To: hdanton, linux-kernel, syzkaller-bugs
Hello,
syzbot has tested the proposed patch and the reproducer did not trigger any issue:
Reported-by: syzbot+80e5d6f453f14a53383a@syzkaller.appspotmail.com
Tested-by: syzbot+80e5d6f453f14a53383a@syzkaller.appspotmail.com
Tested on:
commit: 19272b37 Linux 6.16-rc1
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=17e2ca82580000
kernel config: https://syzkaller.appspot.com/x/.config?x=713d218acd33d94
dashboard link: https://syzkaller.appspot.com/bug?extid=80e5d6f453f14a53383a
compiler: Debian clang version 20.1.6 (++20250514063057+1e4d39e07757-1~exp1~20250514183223.118), Debian LLD 20.1.6
patch: https://syzkaller.appspot.com/x/patch.diff?x=1398f570580000
Note: testing is done by a robot and is best-effort only.
^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [syzbot] [bcachefs?] [rcu?] BUG: unable to handle kernel NULL pointer dereference in rcu_core (3)
2025-06-12 9:37 ` Uladzislau Rezki
@ 2025-06-12 17:20 ` Boqun Feng
0 siblings, 0 replies; 9+ messages in thread
From: Boqun Feng @ 2025-06-12 17:20 UTC (permalink / raw)
To: Uladzislau Rezki (Sony), Aleksandr Nogikh
Cc: syzbot, Andrew Morton, Josh Triplett, kent.overstreet,
linux-bcachefs, linux-kernel, linux-mm, Paul E. McKenney, rcu,
syzkaller-bugs
On Thu, Jun 12, 2025, at 2:37 AM, Uladzislau Rezki wrote:
> On Thu, Jun 12, 2025 at 09:42:32AM +0200, Aleksandr Nogikh wrote:
>> On Wed, Jun 11, 2025 at 10:58 PM Boqun Feng <boqun.feng@gmail.com> wrote:
>> >
>> > On Wed, Jun 11, 2025 at 12:57:04PM -0700, syzbot wrote:
>> > > Hello,
>> > >
>> > > syzbot has tested the proposed patch and the reproducer did not trigger any issue:
>> > >
>> > > Reported-by: syzbot+80e5d6f453f14a53383a@syzkaller.appspotmail.com
>> > > Tested-by: syzbot+80e5d6f453f14a53383a@syzkaller.appspotmail.com
>> > >
>> > > Tested on:
>> > >
>> > > commit: 488ef356 KEYS: Invert FINAL_PUT bit
>> > > git tree: upstream
>> > > console output: https://syzkaller.appspot.com/x/log.txt?x=129a660c580000
>> >
>> > Is there a way to see the whole console output? If Ulad's patch fixes
>> > the exact issue, we should be able to see a WARN_ON_ONCE() triggered.
>>
>> If WARN_ON_ONCE() were triggered, the associated kernel panic output
>> would have been at the end of this log.
>>
>> >
>> > Regards,
>> > Boqun
>> >
>> > > kernel config: https://syzkaller.appspot.com/x/.config?x=713d218acd33d94
>> > > dashboard link: https://syzkaller.appspot.com/bug?extid=80e5d6f453f14a53383a
>>
>> FWIW the last time the bug was observed on syzbot was 100 days ago, so
>> it has likely been fixed since then or has become much harder to
>> reproduce.
>>
> That is even worse, if it is last for 100 days already.
>
My understanding is that the evidence shows that the
issue that directly caused null-ptr-derek the has been
fixed 100 days ago.
Regards,
Boqun
> --
> Uladzislau Rezki
^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [syzbot] [bcachefs?] [rcu?] BUG: unable to handle kernel NULL pointer dereference in rcu_core (3)
2025-06-12 7:42 ` Aleksandr Nogikh
@ 2025-06-12 9:37 ` Uladzislau Rezki
2025-06-12 17:20 ` Boqun Feng
0 siblings, 1 reply; 9+ messages in thread
From: Uladzislau Rezki @ 2025-06-12 9:37 UTC (permalink / raw)
To: Aleksandr Nogikh
Cc: Boqun Feng, syzbot, akpm, josh, kent.overstreet, linux-bcachefs,
linux-kernel, linux-mm, paulmck, rcu, syzkaller-bugs, urezki
On Thu, Jun 12, 2025 at 09:42:32AM +0200, Aleksandr Nogikh wrote:
> On Wed, Jun 11, 2025 at 10:58 PM Boqun Feng <boqun.feng@gmail.com> wrote:
> >
> > On Wed, Jun 11, 2025 at 12:57:04PM -0700, syzbot wrote:
> > > Hello,
> > >
> > > syzbot has tested the proposed patch and the reproducer did not trigger any issue:
> > >
> > > Reported-by: syzbot+80e5d6f453f14a53383a@syzkaller.appspotmail.com
> > > Tested-by: syzbot+80e5d6f453f14a53383a@syzkaller.appspotmail.com
> > >
> > > Tested on:
> > >
> > > commit: 488ef356 KEYS: Invert FINAL_PUT bit
> > > git tree: upstream
> > > console output: https://syzkaller.appspot.com/x/log.txt?x=129a660c580000
> >
> > Is there a way to see the whole console output? If Ulad's patch fixes
> > the exact issue, we should be able to see a WARN_ON_ONCE() triggered.
>
> If WARN_ON_ONCE() were triggered, the associated kernel panic output
> would have been at the end of this log.
>
> >
> > Regards,
> > Boqun
> >
> > > kernel config: https://syzkaller.appspot.com/x/.config?x=713d218acd33d94
> > > dashboard link: https://syzkaller.appspot.com/bug?extid=80e5d6f453f14a53383a
>
> FWIW the last time the bug was observed on syzbot was 100 days ago, so
> it has likely been fixed since then or has become much harder to
> reproduce.
>
That is even worse, if it is last for 100 days already.
--
Uladzislau Rezki
^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [syzbot] [bcachefs?] [rcu?] BUG: unable to handle kernel NULL pointer dereference in rcu_core (3)
2025-06-11 20:58 ` Boqun Feng
@ 2025-06-12 7:42 ` Aleksandr Nogikh
2025-06-12 9:37 ` Uladzislau Rezki
0 siblings, 1 reply; 9+ messages in thread
From: Aleksandr Nogikh @ 2025-06-12 7:42 UTC (permalink / raw)
To: Boqun Feng
Cc: syzbot, akpm, josh, kent.overstreet, linux-bcachefs,
linux-kernel, linux-mm, paulmck, rcu, syzkaller-bugs, urezki
On Wed, Jun 11, 2025 at 10:58 PM Boqun Feng <boqun.feng@gmail.com> wrote:
>
> On Wed, Jun 11, 2025 at 12:57:04PM -0700, syzbot wrote:
> > Hello,
> >
> > syzbot has tested the proposed patch and the reproducer did not trigger any issue:
> >
> > Reported-by: syzbot+80e5d6f453f14a53383a@syzkaller.appspotmail.com
> > Tested-by: syzbot+80e5d6f453f14a53383a@syzkaller.appspotmail.com
> >
> > Tested on:
> >
> > commit: 488ef356 KEYS: Invert FINAL_PUT bit
> > git tree: upstream
> > console output: https://syzkaller.appspot.com/x/log.txt?x=129a660c580000
>
> Is there a way to see the whole console output? If Ulad's patch fixes
> the exact issue, we should be able to see a WARN_ON_ONCE() triggered.
If WARN_ON_ONCE() were triggered, the associated kernel panic output
would have been at the end of this log.
>
> Regards,
> Boqun
>
> > kernel config: https://syzkaller.appspot.com/x/.config?x=713d218acd33d94
> > dashboard link: https://syzkaller.appspot.com/bug?extid=80e5d6f453f14a53383a
FWIW the last time the bug was observed on syzbot was 100 days ago, so
it has likely been fixed since then or has become much harder to
reproduce.
> > compiler: Debian clang version 20.1.6 (++20250514063057+1e4d39e07757-1~exp1~20250514183223.118), Debian LLD 20.1.6
> > patch: https://syzkaller.appspot.com/x/patch.diff?x=170e460c580000
> >
> > Note: testing is done by a robot and is best-effort only.
> >
>
--
Aleksandr
^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [syzbot] [bcachefs?] [rcu?] BUG: unable to handle kernel NULL pointer dereference in rcu_core (3)
2025-06-11 19:57 ` syzbot
@ 2025-06-11 20:58 ` Boqun Feng
2025-06-12 7:42 ` Aleksandr Nogikh
0 siblings, 1 reply; 9+ messages in thread
From: Boqun Feng @ 2025-06-11 20:58 UTC (permalink / raw)
To: syzbot
Cc: akpm, josh, kent.overstreet, linux-bcachefs, linux-kernel,
linux-mm, paulmck, rcu, syzkaller-bugs, urezki
On Wed, Jun 11, 2025 at 12:57:04PM -0700, syzbot wrote:
> Hello,
>
> syzbot has tested the proposed patch and the reproducer did not trigger any issue:
>
> Reported-by: syzbot+80e5d6f453f14a53383a@syzkaller.appspotmail.com
> Tested-by: syzbot+80e5d6f453f14a53383a@syzkaller.appspotmail.com
>
> Tested on:
>
> commit: 488ef356 KEYS: Invert FINAL_PUT bit
> git tree: upstream
> console output: https://syzkaller.appspot.com/x/log.txt?x=129a660c580000
Is there a way to see the whole console output? If Ulad's patch fixes
the exact issue, we should be able to see a WARN_ON_ONCE() triggered.
Regards,
Boqun
> kernel config: https://syzkaller.appspot.com/x/.config?x=713d218acd33d94
> dashboard link: https://syzkaller.appspot.com/bug?extid=80e5d6f453f14a53383a
> compiler: Debian clang version 20.1.6 (++20250514063057+1e4d39e07757-1~exp1~20250514183223.118), Debian LLD 20.1.6
> patch: https://syzkaller.appspot.com/x/patch.diff?x=170e460c580000
>
> Note: testing is done by a robot and is best-effort only.
>
^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [syzbot] [bcachefs?] [rcu?] BUG: unable to handle kernel NULL pointer dereference in rcu_core (3)
2025-06-11 19:15 ` Uladzislau Rezki
@ 2025-06-11 19:57 ` syzbot
2025-06-11 20:58 ` Boqun Feng
0 siblings, 1 reply; 9+ messages in thread
From: syzbot @ 2025-06-11 19:57 UTC (permalink / raw)
To: akpm, josh, kent.overstreet, linux-bcachefs, linux-kernel,
linux-mm, paulmck, rcu, syzkaller-bugs, urezki
Hello,
syzbot has tested the proposed patch and the reproducer did not trigger any issue:
Reported-by: syzbot+80e5d6f453f14a53383a@syzkaller.appspotmail.com
Tested-by: syzbot+80e5d6f453f14a53383a@syzkaller.appspotmail.com
Tested on:
commit: 488ef356 KEYS: Invert FINAL_PUT bit
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=129a660c580000
kernel config: https://syzkaller.appspot.com/x/.config?x=713d218acd33d94
dashboard link: https://syzkaller.appspot.com/bug?extid=80e5d6f453f14a53383a
compiler: Debian clang version 20.1.6 (++20250514063057+1e4d39e07757-1~exp1~20250514183223.118), Debian LLD 20.1.6
patch: https://syzkaller.appspot.com/x/patch.diff?x=170e460c580000
Note: testing is done by a robot and is best-effort only.
^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [syzbot] [bcachefs?] [rcu?] BUG: unable to handle kernel NULL pointer dereference in rcu_core (3)
2025-06-11 18:02 ` [syzbot] [bcachefs?] [rcu?] " syzbot
@ 2025-06-11 19:15 ` Uladzislau Rezki
2025-06-11 19:57 ` syzbot
0 siblings, 1 reply; 9+ messages in thread
From: Uladzislau Rezki @ 2025-06-11 19:15 UTC (permalink / raw)
To: syzbot
Cc: akpm, josh, kent.overstreet, linux-bcachefs, linux-kernel,
linux-mm, paulmck, rcu, syzkaller-bugs, urezki
On Wed, Jun 11, 2025 at 11:02:03AM -0700, syzbot wrote:
> Hello,
>
> syzbot tried to test the proposed patch but the build/boot failed:
>
> failed to apply patch:
> checking file kernel/rcu/tree.c
> patch: **** unexpected end of file in patch
>
>
>
> Tested on:
>
> commit: aef17cb3 Revert "mm/damon/Kconfig: enable CONFIG_DAMON..
> git tree: upstream
> kernel config: https://syzkaller.appspot.com/x/.config?x=523d3ff8e053340a
> dashboard link: https://syzkaller.appspot.com/bug?extid=80e5d6f453f14a53383a
> compiler:
> patch: https://syzkaller.appspot.com/x/patch.diff?x=17de99d4580000
>
#syz test
diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index e8a4b720d7d2..14d4499c6fc3 100644
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -3072,6 +3072,10 @@ __call_rcu_common(struct rcu_head *head, rcu_callback_t func, bool lazy_in)
/* Misaligned rcu_head! */
WARN_ON_ONCE((unsigned long)head & (sizeof(void *) - 1));
+ /* Avoid NULL dereference if callback is NULL. */
+ if (WARN_ON_ONCE(!func))
+ return;
+
if (debug_rcu_head_queue(head)) {
/*
* Probable double call_rcu(), so leak the callback.
^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [syzbot] [bcachefs?] [rcu?] BUG: unable to handle kernel NULL pointer dereference in rcu_core (3)
2025-06-11 15:58 [syzbot] [rcu?] [bcachefs?] " Uladzislau Rezki
@ 2025-06-11 18:02 ` syzbot
2025-06-11 19:15 ` Uladzislau Rezki
0 siblings, 1 reply; 9+ messages in thread
From: syzbot @ 2025-06-11 18:02 UTC (permalink / raw)
To: akpm, josh, kent.overstreet, linux-bcachefs, linux-kernel,
linux-mm, paulmck, rcu, syzkaller-bugs, urezki
Hello,
syzbot tried to test the proposed patch but the build/boot failed:
failed to apply patch:
checking file kernel/rcu/tree.c
patch: **** unexpected end of file in patch
Tested on:
commit: aef17cb3 Revert "mm/damon/Kconfig: enable CONFIG_DAMON..
git tree: upstream
kernel config: https://syzkaller.appspot.com/x/.config?x=523d3ff8e053340a
dashboard link: https://syzkaller.appspot.com/bug?extid=80e5d6f453f14a53383a
compiler:
patch: https://syzkaller.appspot.com/x/patch.diff?x=17de99d4580000
^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [syzbot] [bcachefs?] [rcu?] BUG: unable to handle kernel NULL pointer dereference in rcu_core (3)
2025-02-05 0:34 [syzbot] [rcu?] [bcachefs?] " syzbot
@ 2025-06-08 6:58 ` syzbot
0 siblings, 0 replies; 9+ messages in thread
From: syzbot @ 2025-06-08 6:58 UTC (permalink / raw)
To: akpm, ayaanmirza.788, ayaanmirzabaig85, josh, kent.overstreet,
linux-bcachefs, linux-kernel, linux-mm, luto, paulmck, peterz,
rcu, syzkaller-bugs, tglx
syzbot has bisected this issue to:
commit 14152654805256d760315ec24e414363bfa19a06
Author: Kent Overstreet <kent.overstreet@linux.dev>
Date: Mon Nov 25 05:21:27 2024 +0000
bcachefs: Bad btree roots are now autofix
bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=12fa0a82580000
start commit: 99fa936e8e4f Merge tag 'affs-6.14-rc5-tag' of git://git.ke..
git tree: upstream
final oops: https://syzkaller.appspot.com/x/report.txt?x=11fa0a82580000
console output: https://syzkaller.appspot.com/x/log.txt?x=16fa0a82580000
kernel config: https://syzkaller.appspot.com/x/.config?x=523d3ff8e053340a
dashboard link: https://syzkaller.appspot.com/bug?extid=80e5d6f453f14a53383a
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=119d35a8580000
Reported-by: syzbot+80e5d6f453f14a53383a@syzkaller.appspotmail.com
Fixes: 141526548052 ("bcachefs: Bad btree roots are now autofix")
For information about bisection process see: https://goo.gl/tpsmEJ#bisection
^ permalink raw reply [flat|nested] 9+ messages in thread
end of thread, other threads:[~2025-06-12 17:20 UTC | newest]
Thread overview: 9+ messages (download: mbox.gz / follow: Atom feed)
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[not found] <20250609052925.971-1-hdanton@sina.com>
2025-06-09 6:01 ` [syzbot] [bcachefs?] [rcu?] BUG: unable to handle kernel NULL pointer dereference in rcu_core (3) syzbot
2025-06-11 15:58 [syzbot] [rcu?] [bcachefs?] " Uladzislau Rezki
2025-06-11 18:02 ` [syzbot] [bcachefs?] [rcu?] " syzbot
2025-06-11 19:15 ` Uladzislau Rezki
2025-06-11 19:57 ` syzbot
2025-06-11 20:58 ` Boqun Feng
2025-06-12 7:42 ` Aleksandr Nogikh
2025-06-12 9:37 ` Uladzislau Rezki
2025-06-12 17:20 ` Boqun Feng
-- strict thread matches above, loose matches on Subject: below --
2025-02-05 0:34 [syzbot] [rcu?] [bcachefs?] " syzbot
2025-06-08 6:58 ` [syzbot] [bcachefs?] [rcu?] " syzbot
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