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KCSAN: data-race in filemap_read / generic_write_end

Status: auto-closed as invalid on 2021/06/25 01:21
Subsystems: ext4
[Documentation on labels]
First crash: 1242d, last: 1233d
Similar bugs (2)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KCSAN: data-race in filemap_read / generic_write_end (3) ext4 296 468d 977d 0/28 auto-obsoleted due to no activity on 2023/07/29 13:16
upstream KCSAN: data-race in filemap_read / generic_write_end (2) ext4 8 1102d 1175d 0/28 auto-closed as invalid on 2021/11/02 13:17

Sample crash report:
==================================================================
BUG: KCSAN: data-race in filemap_read / generic_write_end

write to 0xffff888106aef210 of 8 bytes by task 20582 on cpu 1:
 i_size_write include/linux/fs.h:871 [inline]
 generic_write_end+0x96/0x180 fs/buffer.c:2207
 ext4_da_write_end+0x59b/0x730 fs/ext4/inode.c:3110
 generic_perform_write+0x23e/0x3a0 mm/filemap.c:3671
 ext4_buffered_write_iter+0x2f2/0x3f0 fs/ext4/file.c:269
 ext4_file_write_iter+0x2e7/0x11d0 fs/ext4/file.c:519
 call_write_iter include/linux/fs.h:2114 [inline]
 do_iter_readv_writev+0x2cb/0x360 fs/read_write.c:740
 do_iter_write+0x112/0x4c0 fs/read_write.c:866
 vfs_iter_write+0x4c/0x70 fs/read_write.c:907
 iter_file_splice_write+0x40a/0x750 fs/splice.c:689
 do_splice_from fs/splice.c:767 [inline]
 direct_splice_actor+0x80/0xa0 fs/splice.c:936
 splice_direct_to_actor+0x345/0x650 fs/splice.c:891
 do_splice_direct+0xf5/0x170 fs/splice.c:979
 do_sendfile+0x773/0xda0 fs/read_write.c:1260
 __do_sys_sendfile64 fs/read_write.c:1325 [inline]
 __se_sys_sendfile64 fs/read_write.c:1311 [inline]
 __x64_sys_sendfile64+0xf2/0x130 fs/read_write.c:1311
 do_syscall_64+0x4a/0x90 arch/x86/entry/common.c:47
 entry_SYSCALL_64_after_hwframe+0x44/0xae

read to 0xffff888106aef210 of 8 bytes by task 20602 on cpu 0:
 i_size_read include/linux/fs.h:849 [inline]
 filemap_read+0xd68/0x1230 mm/filemap.c:2562
 generic_file_read_iter+0x75/0x2c0 mm/filemap.c:2701
 ext4_file_read_iter+0x1db/0x290 fs/ext4/file.c:73
 call_read_iter include/linux/fs.h:2108 [inline]
 generic_file_splice_read+0x22a/0x310 fs/splice.c:311
 do_splice_to fs/splice.c:796 [inline]
 splice_direct_to_actor+0x2aa/0x650 fs/splice.c:870
 do_splice_direct+0xf5/0x170 fs/splice.c:979
 do_sendfile+0x773/0xda0 fs/read_write.c:1260
 __do_sys_sendfile64 fs/read_write.c:1325 [inline]
 __se_sys_sendfile64 fs/read_write.c:1311 [inline]
 __x64_sys_sendfile64+0xf2/0x130 fs/read_write.c:1311
 do_syscall_64+0x4a/0x90 arch/x86/entry/common.c:47
 entry_SYSCALL_64_after_hwframe+0x44/0xae

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 20602 Comm: syz-executor.5 Not tainted 5.13.0-rc2-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================

Crashes (3):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2021/05/21 01:17 upstream ba816d3c265c 3c7fef33 .config console log report info ci2-upstream-kcsan-gce KCSAN: data-race in filemap_read / generic_write_end
2021/05/20 23:54 upstream f01da525b3de 3c7fef33 .config console log report info ci2-upstream-kcsan-gce KCSAN: data-race in filemap_read / generic_write_end
2021/05/12 06:52 upstream 88b06399c9c7 86294427 .config console log report info ci2-upstream-kcsan-gce KCSAN: data-race in filemap_read / generic_write_end
* Struck through repros no longer work on HEAD.