syzbot


KCSAN: data-race in __es_find_extent_range / ext4_es_lookup_extent

Status: auto-closed as invalid on 2020/12/21 12:00
Subsystems: ext4
[Documentation on labels]
Reported-by: syzbot+ddc9f8c6a385600b6dbb@syzkaller.appspotmail.com
First crash: 1259d, last: 1259d
Similar bugs (5)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KCSAN: data-race in __es_find_extent_range / ext4_es_lookup_extent (2) ext4 2 1202d 1209d 0/26 auto-closed as invalid on 2021/02/11 08:14
upstream KCSAN: data-race in __es_find_extent_range / ext4_es_lookup_extent (6) ext4 1 874d 874d 0/26 auto-closed as invalid on 2022/01/05 07:12
upstream KCSAN: data-race in __es_find_extent_range / ext4_es_lookup_extent (4) ext4 2 1067d 1071d 0/26 auto-closed as invalid on 2021/06/26 18:17
upstream KCSAN: data-race in __es_find_extent_range / ext4_es_lookup_extent (3) ext4 1 1108d 1108d 0/26 auto-closed as invalid on 2021/05/17 10:01
upstream KCSAN: data-race in __es_find_extent_range / ext4_es_lookup_extent (5) ext4 4 980d 1025d 0/26 auto-closed as invalid on 2021/09/22 04:33

Sample crash report:
==================================================================
BUG: KCSAN: data-race in __es_find_extent_range / ext4_es_lookup_extent

read to 0xffff88801263b948 of 8 bytes by task 12026 on cpu 0:
 ext4_es_lookup_extent+0xac/0x500 fs/ext4/extents_status.c:937
 ext4_da_map_blocks fs/ext4/inode.c:1705 [inline]
 ext4_da_get_block_prep+0x14e/0x9a0 fs/ext4/inode.c:1826
 ext4_block_write_begin+0x3f0/0xaa0 fs/ext4/inode.c:1068
 ext4_da_write_begin+0x50a/0xaf0 fs/ext4/inode.c:3007
 generic_perform_write+0x196/0x3a0 mm/filemap.c:3311
 ext4_buffered_write_iter+0x2e5/0x3d0 fs/ext4/file.c:270
 ext4_file_write_iter+0x45e/0x1090 fs/ext4/file.c:503
 call_write_iter include/linux/fs.h:1887 [inline]
 do_iter_readv_writev+0x2cb/0x360 fs/read_write.c:740
 do_iter_write+0x112/0x4b0 fs/read_write.c:866
 vfs_iter_write+0x4c/0x70 fs/read_write.c:907
 iter_file_splice_write+0x42a/0x780 fs/splice.c:686
 do_splice_from fs/splice.c:764 [inline]
 direct_splice_actor+0x80/0xa0 fs/splice.c:933
 splice_direct_to_actor+0x345/0x650 fs/splice.c:888
 do_splice_direct+0xf5/0x170 fs/splice.c:976
 do_sendfile+0x574/0xb70 fs/read_write.c:1257
 __do_sys_sendfile64 fs/read_write.c:1318 [inline]
 __se_sys_sendfile64 fs/read_write.c:1304 [inline]
 __x64_sys_sendfile64+0xf2/0x130 fs/read_write.c:1304
 do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

write to 0xffff88801263b948 of 8 bytes by task 12028 on cpu 1:
 __es_find_extent_range+0x28e/0x330 fs/ext4/extents_status.c:298
 ext4_es_find_extent_range+0x8a/0x200 fs/ext4/extents_status.c:320
 ext4_ext_put_gap_in_cache fs/ext4/extents.c:2237 [inline]
 ext4_ext_map_blocks+0xb96/0x1fc0 fs/ext4/extents.c:4143
 ext4_map_blocks+0x1cc/0xfc0 fs/ext4/inode.c:553
 ext4_mpage_readpages+0x718/0x1360 fs/ext4/readpage.c:304
 ext4_readahead+0x99/0xa0 fs/ext4/inode.c:3252
 read_pages+0xa0/0x6e0 mm/readahead.c:130
 page_cache_ra_unbounded+0x464/0x4c0 mm/readahead.c:238
 ondemand_readahead+0x560/0x780 mm/readahead.c:267
 page_cache_sync_ra+0x1ab/0x1c0 mm/readahead.c:577
 page_cache_sync_readahead include/linux/pagemap.h:839 [inline]
 generic_file_buffered_read+0x38d/0x2110 mm/filemap.c:2227
 generic_file_read_iter+0x80/0x3d0 mm/filemap.c:2535
 ext4_file_read_iter+0x2d0/0x420 fs/ext4/file.c:74
 call_read_iter include/linux/fs.h:1881 [inline]
 generic_file_splice_read+0x22a/0x310 fs/splice.c:311
 do_splice_to fs/splice.c:788 [inline]
 splice_direct_to_actor+0x2aa/0x650 fs/splice.c:867
 do_splice_direct+0xf5/0x170 fs/splice.c:976
 do_sendfile+0x574/0xb70 fs/read_write.c:1257
 __do_sys_sendfile64 fs/read_write.c:1318 [inline]
 __se_sys_sendfile64 fs/read_write.c:1304 [inline]
 __x64_sys_sendfile64+0xf2/0x130 fs/read_write.c:1304
 do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 12028 Comm: syz-executor.2 Not tainted 5.10.0-rc3-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2020/11/11 17:09 upstream eccc87672492 cca87986 .config console log report info ci2-upstream-kcsan-gce
* Struck through repros no longer work on HEAD.