syzbot


KASAN: null-ptr-deref Write in xfs_filestream_select_ag (2)

Status: fixed on 2024/11/14 10:09
Subsystems: xfs
[Documentation on labels]
Reported-by: syzbot+4125a3c514e3436a02e6@syzkaller.appspotmail.com
Fix commit: dc60992ce76f xfs: fix finding a last resort AG in xfs_filestream_pick_ag
First crash: 64d, last: 47d
Discussions (2)
Title Replies (including bot) Last reply
[syzbot] [xfs?] KASAN: null-ptr-deref Write in xfs_filestream_select_ag (2) 4 (9) 2024/10/22 10:11
[PATCH] xfs: If unable to pick perag an error needs to be returned 2 (2) 2024/10/21 13:51
Similar bugs (1)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KASAN: null-ptr-deref Write in xfs_filestream_select_ag xfs C done done 18 345d 623d 0/28 auto-obsoleted due to no activity on 2024/04/02 22:17
Last patch testing requests (4)
Created Duration User Patch Repo Result
2024/10/22 09:41 20m hch@infradead.org git://git.infradead.org/users/hch/misc.git xfs-filesystems-pick-fix OK log
2024/10/20 05:01 20m eadavis@qq.com patch upstream OK log
2024/10/20 03:35 18m eadavis@qq.com patch upstream OK log
2024/10/20 02:54 16m eadavis@qq.com patch upstream report log
Cause bisection attempts (1)
Created Duration User Patch Repo Result
2024/10/26 17:58 31m bisect upstream error job log

Sample crash report:
==================================================================
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>
==================================================================

Crashes (3):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/10/18 18:59 upstream 4d939780b705 666f77ed .config console log report syz / log [disk image] [vmlinux] [kernel image] [mounted in repro #1] [mounted in repro #2] [mounted in repro #3] ci2-upstream-fs KASAN: null-ptr-deref Write in xfs_filestream_select_ag
2024/10/18 17:45 upstream 4d939780b705 666f77ed .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs KASAN: null-ptr-deref Write in xfs_filestream_select_ag
2024/10/01 08:27 upstream e32cde8d2bd7 bbd4e0a4 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root KASAN: null-ptr-deref Write in xfs_filestream_select_ag
* Struck through repros no longer work on HEAD.