Re: [syzbot] Re: [syzbot] [bcachefs?] KMSAN: uninit-value in bch2_copygc

[syzbot <syzbot+8689d10f1894eedf774d@syzkaller.appspotmail.com>]

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Subject: Re: [syzbot] [bcachefs?] KMSAN: uninit-value in bch2_copygc
Author: surajsonawane0215@gmail.com

#syz test

On Sat, Nov 9, 2024 at 8:12 AM syzbot <
syzbot+8689d10f1894eedf774d@syzkaller.appspotmail.com> wrote:

> Hello,
>
> syzbot found the following issue on:
>
> HEAD commit:    2e1b3cc9d7f7 Merge tag 'arm-fixes-6.12-2' of
> git://git.ker..
> git tree:       upstream
> console+strace: https://syzkaller.appspot.com/x/log.txt?x=11361d5f980000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=6fdf74cce377223b
> dashboard link:
> https://syzkaller.appspot.com/bug?extid=8689d10f1894eedf774d
> compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for
> Debian) 2.40
> syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=12348f40580000
> C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=11e7b587980000
>
> Downloadable assets:
> disk image:
> https://storage.googleapis.com/syzbot-assets/08456e37db58/disk-2e1b3cc9.raw.xz
> vmlinux:
> https://storage.googleapis.com/syzbot-assets/cc957f7ba80b/vmlinux-2e1b3cc9.xz
> kernel image:
> https://storage.googleapis.com/syzbot-assets/7579fe72ed89/bzImage-2e1b3cc9.xz
> mounted in repro:
> https://storage.googleapis.com/syzbot-assets/5903d7d7fe58/mount_4.gz
>
> IMPORTANT: if you fix the issue, please add the following tag to the
> commit:
> Reported-by: syzbot+8689d10f1894eedf774d@syzkaller.appspotmail.com
>
> =====================================================
> BUG: KMSAN: uninit-value in rht_ptr_rcu include/linux/rhashtable.h:376
> [inline]
> BUG: KMSAN: uninit-value in __rhashtable_lookup
> include/linux/rhashtable.h:607 [inline]
> BUG: KMSAN: uninit-value in rhashtable_lookup
> include/linux/rhashtable.h:646 [inline]
> BUG: KMSAN: uninit-value in rhashtable_lookup_fast
> include/linux/rhashtable.h:672 [inline]
> BUG: KMSAN: uninit-value in bucket_in_flight fs/bcachefs/movinggc.c:144
> [inline]
> BUG: KMSAN: uninit-value in bch2_copygc_get_buckets
> fs/bcachefs/movinggc.c:170 [inline]
> BUG: KMSAN: uninit-value in bch2_copygc+0x1d3f/0x58f0
> fs/bcachefs/movinggc.c:221
>  rht_ptr_rcu include/linux/rhashtable.h:376 [inline]
>  __rhashtable_lookup include/linux/rhashtable.h:607 [inline]
>  rhashtable_lookup include/linux/rhashtable.h:646 [inline]
>  rhashtable_lookup_fast include/linux/rhashtable.h:672 [inline]
>  bucket_in_flight fs/bcachefs/movinggc.c:144 [inline]
>  bch2_copygc_get_buckets fs/bcachefs/movinggc.c:170 [inline]
>  bch2_copygc+0x1d3f/0x58f0 fs/bcachefs/movinggc.c:221
>  bch2_copygc_thread+0x7f7/0xfa0 fs/bcachefs/movinggc.c:381
>  kthread+0x3e2/0x540 kernel/kthread.c:389
>  ret_from_fork+0x6d/0x90 arch/x86/kernel/process.c:147
>  ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
>
> Local variable b205.i created at:
>  bch2_copygc_get_buckets fs/bcachefs/movinggc.c:170 [inline]
>  bch2_copygc+0x15b3/0x58f0 fs/bcachefs/movinggc.c:221
>  bch2_copygc_thread+0x7f7/0xfa0 fs/bcachefs/movinggc.c:381
>
> CPU: 0 UID: 0 PID: 5796 Comm: bch-copygc/loop Not tainted
> 6.12.0-rc6-syzkaller-00077-g2e1b3cc9d7f7 #0
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
> Google 09/13/2024
> =====================================================
> Kernel panic - not syncing: kmsan.panic set ...
> CPU: 0 UID: 0 PID: 5796 Comm: bch-copygc/loop Tainted: G    B
> 6.12.0-rc6-syzkaller-00077-g2e1b3cc9d7f7 #0
> Tainted: [B]=BAD_PAGE
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
> Google 09/13/2024
> Call Trace:
>  <TASK>
>  __dump_stack lib/dump_stack.c:94 [inline]
>  dump_stack_lvl+0x216/0x2d0 lib/dump_stack.c:120
>  dump_stack+0x1e/0x30 lib/dump_stack.c:129
>  panic+0x4e2/0xcf0 kernel/panic.c:354
>  kmsan_report+0x2c7/0x2d0 mm/kmsan/report.c:218
>  __msan_warning+0x95/0x120 mm/kmsan/instrumentation.c:318
>  rht_ptr_rcu include/linux/rhashtable.h:376 [inline]
>  __rhashtable_lookup include/linux/rhashtable.h:607 [inline]
>  rhashtable_lookup include/linux/rhashtable.h:646 [inline]
>  rhashtable_lookup_fast include/linux/rhashtable.h:672 [inline]
>  bucket_in_flight fs/bcachefs/movinggc.c:144 [inline]
>  bch2_copygc_get_buckets fs/bcachefs/movinggc.c:170 [inline]
>  bch2_copygc+0x1d3f/0x58f0 fs/bcachefs/movinggc.c:221
>  bch2_copygc_thread+0x7f7/0xfa0 fs/bcachefs/movinggc.c:381
>  kthread+0x3e2/0x540 kernel/kthread.c:389
>  ret_from_fork+0x6d/0x90 arch/x86/kernel/process.c:147
>  ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
>  </TASK>
> Kernel Offset: disabled
> Rebooting in 86400 seconds..
>
>
> ---
> This report is generated by a bot. It may contain errors.
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>
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