linux-kernel - Re: WARNING in __folio_mark

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Message-ID: <CAHc6FU6O9ys6cbwOBmgz9e3EZgNDSRnnm6c=056VdJKF490ixQ@mail.gmail.com>
Date: Fri, 2 May 2025 11:52:13 +0200
From: Andreas Gruenbacher <agruenba@...hat.com>
To: Andrew Morton <akpm@...ux-foundation.org>
Cc: "huk23@...udan.edu.cn" <huk23@...udan.edu.cn>, "jjtan24@...udan.edu.cn" <jjtan24@...udan.edu.cn>, 
	白烁冉 <baishuoran@...eu.edu.cn>, 
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>, 
	"syzkaller@...glegroups.com" <syzkaller@...glegroups.com>, linux-fsdevel <linux-fsdevel@...r.kernel.org>, 
	linux-mm <linux-mm@...ck.org>, gfs2@...ts.linux.dev
Subject: Re: WARNING in __folio_mark_dirty

On Fri, May 2, 2025 at 5:36 AM Andrew Morton <akpm@...ux-foundation.org> wrote:
> On Fri, 2 May 2025 03:26:20 +0000 "huk23@...udan.edu.cn" <huk23@...udan.edu.cn> wrote:
> > Dear Maintainers，
>
> Let's Cc the gfs2 developers.

On gfs2, these warnings should be fixed by the following two commits:

9e888998ea4d ("writeback: fix false warning in inode_to_wb()")
ae9f3bd8259a ("gfs2: replace sd_aspace with sd_inode")

The first one is in v6.15-rc3 thanks to Andrew; the second one is on
gfs2's for-next branch right now:

https://git.kernel.org/pub/scm/linux/kernel/git/gfs2/linux-gfs2.git/commit/?h=for-next&id=ae9f3bd8259a

> Do you know if this is reproducible on any other filesystem?
>
> >
> > When using our customized Syzkaller to fuzz the latest Linux kernel, the following crash (37th and 76th)was triggered.
> >
> >
> > 37th：
> > HEAD commit: 6537cfb395f352782918d8ee7b7f10ba2cc3cbf2
> > git tree: upstream
> > Output:https://github.com/pghk13/Kernel-Bug/blob/main/1220_6.13rc_KASAN/2.%E5%9B%9E%E5%BD%92-11/14-KASAN_%20slab-out-of-bounds%20Read%20in%20hfsplus_bnode_read/14call_trace.txt
> > Kernel config:https://github.com/pghk13/Kernel-Bug/blob/main/0305_6.15rc1/config.txt
> > C reproducer:https://github.com/pghk13/Kernel-Bug/blob/main/0219_6.13rc7_todo/76-UBSAN_%20shift-out-of-bounds%20in%20bch2_trans_iter_init_outlined/37repro.c
> > Syzlang reproducer: https://github.com/pghk13/Kernel-Bug/blob/main/0219_6.13rc7_todo/76-UBSAN_%20shift-out-of-bounds%20in%20bch2_trans_iter_init_outlined/37repro.txt
> >
> > 76th：
> > HEAD commit: 6537cfb395f352782918d8ee7b7f10ba2cc3cbf2
> > git tree: upstream
> > Output:https://github.com/pghk13/Kernel-Bug/blob/main/0219_6.13rc7_todo/76-UBSAN_%20shift-out-of-bounds%20in%20bch2_trans_iter_init_outlined/76call_trace.txt
> > Kernel config:https://github.com/pghk13/Kernel-Bug/blob/main/0305_6.15rc1/config.txt
> > C reproducer:https://github.com/pghk13/Kernel-Bug/blob/main/0219_6.13rc7_todo/76-UBSAN_%20shift-out-of-bounds%20in%20bch2_trans_iter_init_outlined/76repro.c
> > Syzlang reproducer: https://github.com/pghk13/Kernel-Bug/blob/main/0219_6.13rc7_todo/76-UBSAN_%20shift-out-of-bounds%20in%20bch2_trans_iter_init_outlined/76repro.txt
> >
> >
> >
> > The two errors seem to have the same error points, but there are a few differences in the process. They all trigger warnings in the __folio_mark_dirty+0xb50/0xf10 function of backing-dev.h:251. In __folio_mark_dirty function, a warning is triggered when the code tries to access or modify the backing-dev information. The 76th call stack has longer call chains from file writebacks: writeback work queues → writeback inodes → GFS2 write inodes → log refreshes.
> > We have reproduced this issue several times on 6.15-rc1 again.
> >
> >
> >
> >
> > If you fix this issue, please add the following tag to the commit:
> > Reported-by: Kun Hu <huk23@...udan.edu.cn>, Jiaji Qin <jjtan24@...udan.edu.cn>, Shuoran Bai <baishuoran@...eu.edu.cn>
> >
> >
> >
> > 37th：
> > ==================================================================
> > WARNING: CPU: 2 PID: 9494 at ./include/linux/backing-dev.h:251 __folio_mark_dirty+0xb50/0xf10
> > Modules linked in:
> > CPU: 2 UID: 0 PID: 9494 Comm: gfs2_logd/syz:s Not tainted 6.15.0-rc1 #1 PREEMPT(full)
> > Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-1ubuntu1.1 04/01/2014
> > RIP: 0010:__folio_mark_dirty+0xb50/0xf10
> > Code: ff ff 48 8d 78 70 e8 af e3 76 09 31 ff 89 c6 89 44 24 08 e8 72 d3 c5 ff 8b 44 24 08 85 c0 0f 85 af f9 ff ff e8 51 d1 c5 ff 90 <0f> 0b 90 e9 a1 f9 ff ff e8 43 d1 c5 ff 90 0f 0b 90 e9 59 f5 ff ff
> > RSP: 0018:ffffc90014bb7b18 EFLAGS: 00010046
> > RAX: 0000000000000000 RBX: ffff88804298cb58 RCX: ffffffff81f5408e
> > RDX: 0000000000000000 RSI: ffff888023edc900 RDI: 0000000000000002
> > RBP: ffffea00015c9d80 R08: 0000000000000000 R09: ffffed10085319a0
> > R10: ffffed100853199f R11: ffff88804298ccff R12: 0000000000000246
> > R13: ffff888049bd8bc8 R14: 0000000000000001 R15: 0000000000000001
> > FS:  0000000000000000(0000) GS:ffff888097c6b000(0000) knlGS:0000000000000000
> > CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> > CR2: 00007ff2c7be9028 CR3: 000000000e180000 CR4: 0000000000750ef0
> > PKRU: 55555554
> > Call Trace:
> >  <TASK>
> >  mark_buffer_dirty+0x358/0x410
> >  gfs2_unpin+0x106/0xef0
> >  buf_lo_after_commit+0x155/0x230
> >  gfs2_log_flush+0xd95/0x2cb0
> >  gfs2_logd+0x29b/0x12c0
> >  kthread+0x447/0x8a0
> >  ret_from_fork+0x48/0x80
> >  ret_from_fork_asm+0x1a/0x30
> >  </TASK>
> > extracting prog: 1h56m11.644263162s
> > minimizing prog: 14m12.695891417s
> > simplifying prog options: 0s
> > extracting C: 32.234365976s
> > simplifying C: 9m50.565845853s
> >
> >
> >
> >
> >
> > 76th：
> > ==================================================================
> > WARNING: CPU: 3 PID: 3051 at ./include/linux/backing-dev.h:251 __folio_mark_dirty+0xb50/0xf10
> > Modules linked in:
> > CPU: 3 UID: 0 PID: 3051 Comm: kworker/u18:5 Not tainted 6.15.0-rc1 #1 PREEMPT(full)
> > Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-1ubuntu1.1 04/01/2014
> > Workqueue: writeback wb_workfn (flush-7:0)
> > RIP: 0010:__folio_mark_dirty+0xb50/0xf10
> > Code: ff ff 48 8d 78 70 e8 af e3 76 09 31 ff 89 c6 89 44 24 08 e8 72 d3 c5 ff 8b 44 24 08 85 c0 0f 85 af f9 ff ff e8 51 d1 c5 ff 90 <0f> 0b 90 e9 a1 f9 ff ff e8 43 d1 c5 ff 90 0f 0b 90 e9 59 f5 ff ff
> > RSP: 0018:ffffc90011e2f410 EFLAGS: 00010046
> > RAX: 0000000000000000 RBX: ffff88804266bfd8 RCX: ffffffff81f5408e
> > RDX: 0000000000000000 RSI: ffff888043e48000 RDI: 0000000000000002
> > RBP: ffffea000086e9c0 R08: 0000000000000000 R09: ffffed10084cd830
> > R10: ffffed10084cd82f R11: ffff88804266c17f R12: 0000000000000246
> > R13: ffff888012bf87f0 R14: 0000000000000001 R15: 0000000000000001
> > FS: 0000000000000000(0000) GS:ffff8880eb46b000(0000) knlGS:0000000000000000
> > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> > CR2: 00007f6410e8e140 CR3: 0000000023648000 CR4: 0000000000750ef0
> > PKRU: 55555554
> > Call Trace:
> > <TASK>
> > mark_buffer_dirty+0x358/0x410
> > gfs2_unpin+0x106/0xef0
> > buf_lo_after_commit+0x155/0x230
> > gfs2_log_flush+0xd95/0x2cb0
> > gfs2_write_inode+0x371/0x450
> > __writeback_single_inode+0xad7/0xf50
> > writeback_sb_inodes+0x5f5/0xee0
> > __writeback_inodes_wb+0xbe/0x270
> > wb_writeback+0x728/0xb50
> > wb_workfn+0x96e/0xe90
> > process_scheduled_works+0x5de/0x1bd0
> > worker_thread+0x5a9/0xd10
> > kthread+0x447/0x8a0
> > ret_from_fork+0x48/0x80
> > ret_from_fork_asm+0x1a/0x30
> > </TASK>
> >
> >
> >
> > thanks,
> > Kun Hu
> >
>

Thanks,
Andreas