Re: [syzbot] [raid?] BUG: unable to handle kernel paging request in free_conf

Re: [syzbot] [raid?] BUG: unable to handle kernel paging request in free_conf

[syzbot]

Hello,

syzbot has tested the proposed patch and the reproducer did not trigger any issue:

Reported-by: syzbot+270624bb31d478afe62e@syzkaller.appspotmail.com
Tested-by: syzbot+270624bb31d478afe62e@syzkaller.appspotmail.com

Tested on:

commit:         f0100363 Merge tag 'xfs-fixes-7.3-rc5' of gitolite.ker..
git tree:       git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
console output: https://syzkaller.appspot.com/x/log.txt?x=108bf805580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=2b924f079099ba6e
dashboard link: https://syzkaller.appspot.com/bug?extid=270624bb31d478afe62e
compiler:       Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8
patch:          https://syzkaller.appspot.com/x/patch.diff?x=15ed3805580000

Note: testing is done by a robot and is best-effort only.

[syzbot] [raid?] BUG: unable to handle kernel paging request in free_conf

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit:    f0100363d8c3 Merge tag 'xfs-fixes-7.3-rc5' of gitolite.ker..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=133e5805580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=2b924f079099ba6e
dashboard link: https://syzkaller.appspot.com/bug?extid=270624bb31d478afe62e
compiler:       Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=13db8515580000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=1299b525580000

Downloadable assets:
disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/d900f083ada3/non_bootable_disk-f0100363.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/18fb2734cddb/vmlinux-f0100363.xz
kernel image: https://storage.googleapis.com/syzbot-assets/5737b586e7bc/bzImage-f0100363.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+270624bb31d478afe62e@syzkaller.appspotmail.com

 </TASK>
==================================================================
BUG: KASAN: null-ptr-deref in instrument_atomic_read include/linux/instrumented.h:82 [inline]
BUG: KASAN: null-ptr-deref in _test_bit include/asm-generic/bitops/instrumented-non-atomic.h:141 [inline]
BUG: KASAN: null-ptr-deref in raid5_has_ppl drivers/md/raid5-log.h:54 [inline]
BUG: KASAN: null-ptr-deref in log_exit drivers/md/raid5-log.h:128 [inline]
BUG: KASAN: null-ptr-deref in free_conf+0x81/0x5d0 drivers/md/raid5.c:7549
Read of size 8 at addr 0000000000000028 by task syz.3.20/5681

CPU: 0 UID: 0 PID: 5681 Comm: syz.3.20 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 kasan_report+0x117/0x150 mm/kasan/report.c:595
 check_region_inline mm/kasan/generic.c:-1 [inline]
 kasan_check_range+0x264/0x2c0 mm/kasan/generic.c:200
 instrument_atomic_read include/linux/instrumented.h:82 [inline]
 _test_bit include/asm-generic/bitops/instrumented-non-atomic.h:141 [inline]
 raid5_has_ppl drivers/md/raid5-log.h:54 [inline]
 log_exit drivers/md/raid5-log.h:128 [inline]
 free_conf+0x81/0x5d0 drivers/md/raid5.c:7549
 setup_conf+0x1720/0x2ad0 drivers/md/raid5.c:7885
 raid5_run+0x8cc/0x2560 drivers/md/raid5.c:8129
 md_run+0xc3d/0x1cd0 drivers/md/md.c:6779
 do_md_run+0x35/0x720 drivers/md/md.c:6880
 array_state_store+0x958/0xe90 drivers/md/md.c:-1
 md_attr_store+0x3b7/0x640 drivers/md/md.c:6158
 kernfs_fop_write_iter+0x3a4/0x540 fs/kernfs/file.c:345
 new_sync_write fs/read_write.c:595 [inline]
 vfs_write+0x612/0xba0 fs/read_write.c:687
 ksys_write+0x150/0x270 fs/read_write.c:739
 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
 do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f36cfd9e159
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffe9be823c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f36d0025fa0 RCX: 00007f36cfd9e159
RDX: 0000000000000006 RSI: 0000200000000a40 RDI: 0000000000000008
RBP: 00007ffe9be82430 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001
R13: 00007f36d0025fac R14: 00007f36d0025fa0 R15: 00007f36d0025fa0
 </TASK>
==================================================================


---
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