syzbot


KCSAN: data-race in xas_clear_mark / xas_find_marked (2)

Status: moderation: reported on 2019/12/10 21:55
Subsystems: mm fs
[Documentation on labels]
Reported-by: syzbot+6b653cb0a28eee8c400a@syzkaller.appspotmail.com
First crash: 2315d, last: 1d02h
Similar bugs (1)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KCSAN: data-race in xas_clear_mark / xas_find_marked mm 6 3 2319d 2325d 0/29 closed as invalid on 2019/10/18 14:11

Sample crash report:
EXT4-fs (loop9): encrypted files will use data=ordered instead of data journaling mode
EXT4-fs (loop9): 1 truncate cleaned up
EXT4-fs (loop9): mounted filesystem 00000000-0000-0000-0000-000000000000 r/w without journal. Quota mode: none.
==================================================================
BUG: KCSAN: data-race in xas_clear_mark / xas_find_marked

read-write to 0xffff8881077576c0 of 8 bytes by task 13171 on cpu 1:
 instrument_read_write include/linux/instrumented.h:56 [inline]
 __instrument_read_write_bitop include/asm-generic/bitops/instrumented-non-atomic.h:84 [inline]
 ___test_and_clear_bit include/asm-generic/bitops/instrumented-non-atomic.h:114 [inline]
 node_clear_mark lib/xarray.c:102 [inline]
 xas_clear_mark+0x91/0x180 lib/xarray.c:922
 __folio_start_writeback+0x270/0x370 mm/page-writeback.c:3011
 ext4_bio_write_folio+0x5ad/0x9f0 fs/ext4/page-io.c:584
 mpage_submit_folio fs/ext4/inode.c:2080 [inline]
 mpage_process_page_bufs+0x4a1/0x620 fs/ext4/inode.c:2191
 mpage_prepare_extent_to_map+0x7d4/0xc50 fs/ext4/inode.c:2730
 ext4_do_writepages+0x70f/0x2840 fs/ext4/inode.c:2871
 ext4_writepages+0x18f/0x320 fs/ext4/inode.c:3019
 do_writepages+0x1c6/0x310 mm/page-writeback.c:2554
 filemap_writeback mm/filemap.c:387 [inline]
 filemap_fdatawrite_range mm/filemap.c:412 [inline]
 filemap_write_and_wait_range+0x166/0x370 mm/filemap.c:684
 filemap_write_and_wait include/linux/pagemap.h:65 [inline]
 ext4_ioctl_setflags fs/ext4/ioctl.c:648 [inline]
 ext4_fileattr_set+0x4e6/0xe40 fs/ext4/ioctl.c:1027
 vfs_fileattr_set+0x666/0x6b0 fs/file_attr.c:301
 ioctl_setflags+0x14b/0x180 fs/file_attr.c:337
 do_vfs_ioctl+0x661/0xe70 fs/ioctl.c:560
 __do_sys_ioctl fs/ioctl.c:595 [inline]
 __se_sys_ioctl+0x82/0x140 fs/ioctl.c:583
 __x64_sys_ioctl+0x43/0x50 fs/ioctl.c:583
 x64_sys_call+0x1563/0x3020 arch/x86/include/generated/asm/syscalls_64.h:17
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x12c/0x370 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff8881077576c0 of 8 bytes by task 13164 on cpu 0:
 xas_find_chunk include/linux/xarray.h:1752 [inline]
 xas_find_marked+0x213/0x620 lib/xarray.c:1510
 find_get_entry mm/filemap.c:2064 [inline]
 filemap_get_folios_tag+0xfa/0x510 mm/filemap.c:2332
 mpage_prepare_extent_to_map+0x328/0xc50 fs/ext4/inode.c:2632
 ext4_do_writepages+0x70f/0x2840 fs/ext4/inode.c:2871
 ext4_writepages+0x18f/0x320 fs/ext4/inode.c:3019
 do_writepages+0x1c6/0x310 mm/page-writeback.c:2554
 filemap_writeback mm/filemap.c:387 [inline]
 filemap_fdatawrite_range mm/filemap.c:412 [inline]
 file_write_and_wait_range+0x178/0x2f0 mm/filemap.c:786
 generic_buffers_fsync_noflush+0x45/0x130 fs/buffer.c:607
 ext4_fsync_nojournal fs/ext4/fsync.c:88 [inline]
 ext4_sync_file+0x1aa/0x6b0 fs/ext4/fsync.c:147
 vfs_fsync_range+0xc5/0xe0 fs/sync.c:186
 generic_write_sync include/linux/fs.h:2640 [inline]
 ext4_buffered_write_iter+0x34f/0x3c0 fs/ext4/file.c:306
 ext4_file_write_iter+0x380/0xfa0 fs/ext4/file.c:-1
 new_sync_write fs/read_write.c:595 [inline]
 vfs_write+0x5a6/0x9f0 fs/read_write.c:688
 ksys_write+0xdc/0x1a0 fs/read_write.c:740
 __do_sys_write fs/read_write.c:751 [inline]
 __se_sys_write fs/read_write.c:748 [inline]
 __x64_sys_write+0x40/0x50 fs/read_write.c:748
 x64_sys_call+0x27e1/0x3020 arch/x86/include/generated/asm/syscalls_64.h:2
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x12c/0x370 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x003fffff00000000 -> 0x003ffff000000000

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 13164 Comm: syz.9.13498 Tainted: G        W           syzkaller #0 PREEMPT(full) 
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
==================================================================

Crashes (4121):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/02/21 12:02 upstream d79526b89571 6e7b5511 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in xas_clear_mark / xas_find_marked
2026/02/21 04:45 upstream a95f71ad3e2e 6e7b5511 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in xas_clear_mark / xas_find_marked
2026/02/20 21:12 upstream 8bf22c33e7a1 6e7b5511 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in xas_clear_mark / xas_find_marked
2026/02/10 04:43 upstream 8a5203c630c6 4ab09a02 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in xas_clear_mark / xas_find_marked
2026/02/01 02:20 upstream ad9a728a3388 6b8752f2 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in xas_clear_mark / xas_find_marked
2026/01/21 07:40 upstream 6c790212c588 6f1aa2f9 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in xas_clear_mark / xas_find_marked
2026/01/18 02:59 upstream d12453c7e281 20d37d28 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in xas_clear_mark / xas_find_marked
2026/01/03 15:10 upstream 805f9a061372 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in xas_clear_mark / xas_find_marked
2025/12/31 12:27 upstream c8ebd433459b d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in xas_clear_mark / xas_find_marked
2025/12/27 23:58 upstream d26143bb38e2 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in xas_clear_mark / xas_find_marked
2025/11/24 00:12 upstream d0e88704d96c 4fb8ef37 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in xas_clear_mark / xas_find_marked
2025/11/14 09:01 upstream 6da43bbeb691 07e030de .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in xas_clear_mark / xas_find_marked
2025/11/06 13:46 upstream dc77806cf3b4 a6c9c731 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in xas_clear_mark / xas_find_marked
2025/11/02 21:02 upstream 6146a0f1dfae 2c50b6a9 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in xas_clear_mark / xas_find_marked
2025/10/27 19:25 upstream dcb6fa37fd7b fd2207e7 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in xas_clear_mark / xas_find_marked
2025/10/24 13:25 upstream 6fab32bb6508 c0460fcd .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in xas_clear_mark / xas_find_marked
2025/10/23 04:51 upstream dd72c8fcf6d3 c0460fcd .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in xas_clear_mark / xas_find_marked
2025/10/22 02:35 upstream 552c50713f27 9832ed61 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in xas_clear_mark / xas_find_marked
2025/10/21 04:29 upstream 6548d364a3e8 9832ed61 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in xas_clear_mark / xas_find_marked
2025/10/19 21:46 upstream d9043c79ba68 1c8c8cd8 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in xas_clear_mark / xas_find_marked
2025/10/06 18:14 upstream fd94619c4336 91305dbe .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in xas_clear_mark / xas_find_marked
2025/10/02 01:43 upstream 080ffb4bec4d 267f56c6 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in xas_clear_mark / xas_find_marked
2025/09/28 04:57 upstream 51a24b7deaae 001c9061 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in xas_clear_mark / xas_find_marked
2025/09/27 12:42 upstream fec734e8d564 001c9061 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in xas_clear_mark / xas_find_marked
2025/09/20 22:41 upstream 3b08f56fbbb9 67c37560 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in xas_clear_mark / xas_find_marked
2025/09/17 08:00 upstream 5aca7966d2a7 e2beed91 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in xas_clear_mark / xas_find_marked
2025/09/14 21:54 upstream 79e8447ec662 e2beed91 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in xas_clear_mark / xas_find_marked
2025/09/06 04:15 upstream c8ed9b5c02a5 d291dd2d .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in xas_clear_mark / xas_find_marked
2025/08/25 23:33 upstream b6add54ba618 bf27483f .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in xas_clear_mark / xas_find_marked
2025/08/22 04:28 upstream 3957a5720157 bf27483f .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in xas_clear_mark / xas_find_marked
2025/08/13 21:55 upstream dfc0f6373094 22ec1469 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in xas_clear_mark / xas_find_marked
2025/08/10 09:42 upstream 2b38afce25c4 32a0e5ed .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in xas_clear_mark / xas_find_marked
2025/07/29 13:11 upstream ae388edd4a8f c4a95487 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in xas_clear_mark / xas_find_marked
2025/07/27 02:11 upstream 302f88ff3584 fb8f743d .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in xas_clear_mark / xas_find_marked
2025/07/25 17:19 upstream 2942242dde89 fb8f743d .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in xas_clear_mark / xas_find_marked
2025/07/17 04:35 upstream e2291551827f 44f8051e .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in xas_clear_mark / xas_find_marked
2025/07/09 15:25 upstream 733923397fd9 f4e5e155 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in xas_clear_mark / xas_find_marked
2025/07/05 04:59 upstream a79a588fc176 d869b261 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in xas_clear_mark / xas_find_marked
2025/07/04 23:33 upstream 4c06e63b9203 d869b261 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in xas_clear_mark / xas_find_marked
2025/07/03 01:44 upstream b4911fb0b060 bc80e4f0 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in xas_clear_mark / xas_find_marked
2025/06/29 11:06 upstream ded779017ad7 fc9d8ee5 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in xas_clear_mark / xas_find_marked
2025/06/29 11:06 upstream ded779017ad7 fc9d8ee5 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in xas_clear_mark / xas_find_marked
2025/06/26 14:25 upstream ee88bddf7f2f 803ce19b .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in xas_clear_mark / xas_find_marked
2021/01/17 10:22 upstream 0da0a8a0a0e1 813be542 .config console log report info ci2-upstream-kcsan-gce
2019/10/22 14:09 https://github.com/google/ktsan.git kcsan 05f2236801fe 4ee855e7 .config console log report ci2-upstream-kcsan-gce
* Struck through repros no longer work on HEAD.