Message-ID: <6712b052.050a0220.10f4f4.001a.GAE@google.com>
Date: Fri, 18 Oct 2024 12:00:34 -0700
From: syzbot <syzbot+4125a3c514e3436a02e6@...kaller.appspotmail.com>
To: cem@...nel.org, chandan.babu@...cle.com, djwong@...nel.org, 
	linux-kernel@...r.kernel.org, linux-xfs@...r.kernel.org, 
	syzkaller-bugs@...glegroups.com
Subject: [syzbot] [xfs?] KASAN: null-ptr-deref Write in xfs_filestream_select_ag
 (2)

Hello,

syzbot found the following issue on:

HEAD commit:    4d939780b705 Merge tag 'mm-hotfixes-stable-2024-10-17-16-0..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=169f4c5f980000
kernel config:  https://syzkaller.appspot.com/x/.config?x=164d2822debd8b0d
dashboard link: https://syzkaller.appspot.com/bug?extid=4125a3c514e3436a02e6
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=1374d830580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/cbc7a4f0dff1/disk-4d939780.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/21165b36b232/vmlinux-4d939780.xz
kernel image: https://storage.googleapis.com/syzbot-assets/8e42c5595828/bzImage-4d939780.xz
mounted in repro #1: https://storage.googleapis.com/syzbot-assets/9171ce715585/mount_0.gz
mounted in repro #2: https://storage.googleapis.com/syzbot-assets/faf0b43468d6/mount_2.gz
mounted in repro #3: https://storage.googleapis.com/syzbot-assets/12ac0c5a53d1/mount_14.gz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+4125a3c514e3436a02e6@...kaller.appspotmail.com

==================================================================
BUG: KASAN: null-ptr-deref in instrument_atomic_read_write include/linux/instrumented.h:96 [inline]
BUG: KASAN: null-ptr-deref in atomic_inc include/linux/atomic/atomic-instrumented.h:435 [inline]
BUG: KASAN: null-ptr-deref in xfs_filestream_create_association fs/xfs/xfs_filestream.c:320 [inline]
BUG: KASAN: null-ptr-deref in xfs_filestream_select_ag+0x13ed/0x1d80 fs/xfs/xfs_filestream.c:371
Write of size 4 at addr 0000000000000010 by task syz.1.56/5898

CPU: 0 UID: 0 PID: 5898 Comm: syz.1.56 Not tainted 6.12.0-rc3-syzkaller-00217-g4d939780b705 #0
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+0x241/0x360 lib/dump_stack.c:120
 print_report+0xe8/0x550 mm/kasan/report.c:491
 kasan_report+0x143/0x180 mm/kasan/report.c:601
 kasan_check_range+0x282/0x290 mm/kasan/generic.c:189
 instrument_atomic_read_write include/linux/instrumented.h:96 [inline]
 atomic_inc include/linux/atomic/atomic-instrumented.h:435 [inline]
 xfs_filestream_create_association fs/xfs/xfs_filestream.c:320 [inline]
 xfs_filestream_select_ag+0x13ed/0x1d80 fs/xfs/xfs_filestream.c:371
 xfs_bmap_btalloc_filestreams fs/xfs/libxfs/xfs_bmap.c:3657 [inline]
 xfs_bmap_btalloc fs/xfs/libxfs/xfs_bmap.c:3774 [inline]
 xfs_bmapi_allocate+0x162d/0x3450 fs/xfs/libxfs/xfs_bmap.c:4189
 xfs_bmapi_convert_one_delalloc fs/xfs/libxfs/xfs_bmap.c:4697 [inline]
 xfs_bmapi_convert_delalloc+0x9a0/0x1970 fs/xfs/libxfs/xfs_bmap.c:4752
 xfs_map_blocks+0x7b7/0x1050 fs/xfs/xfs_aops.c:363
 iomap_writepage_map_blocks fs/iomap/buffered-io.c:1855 [inline]
 iomap_writepage_map fs/iomap/buffered-io.c:2003 [inline]
 iomap_writepages+0xd49/0x2ac0 fs/iomap/buffered-io.c:2057
 xfs_vm_writepages+0xfc/0x150 fs/xfs/xfs_aops.c:477
 do_writepages+0x35d/0x870 mm/page-writeback.c:2683
 filemap_fdatawrite_wbc+0x125/0x180 mm/filemap.c:398
 __filemap_fdatawrite_range mm/filemap.c:431 [inline]
 file_write_and_wait_range+0x195/0x280 mm/filemap.c:788
 xfs_file_fsync+0x1d3/0xa80 fs/xfs/xfs_file.c:138
 generic_write_sync include/linux/fs.h:2871 [inline]
 xfs_file_buffered_write+0x9a8/0xac0 fs/xfs/xfs_file.c:799
 new_sync_write fs/read_write.c:590 [inline]
 vfs_write+0xa6d/0xc90 fs/read_write.c:683
 ksys_write+0x183/0x2b0 fs/read_write.c:736
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f11d7b7dff9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f11d75de038 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f11d7d36208 RCX: 00007f11d7b7dff9
RDX: 0000000000000048 RSI: 0000000020020cc0 RDI: 0000000000000004
RBP: 00007f11d7bf0296 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f11d7d36208 R15: 00007ffcddfd4a88
 </TASK>
==================================================================


---
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