KCSAN: data-race in ext4_alloc_da_blocks / ext4_da_reserve

KCSAN: data-race in ext4_alloc_da_blocks / ext4_da_reserve_space (4)
Status: auto-closed as invalid on 2020/11/07 06:53
Reported-by: syzbot+@syzkaller.appspotmail.com
First crash: 398d, last: 298d

similar bugs (4):
Kernel	Title	Count	Last	Reported	Patched	Status
upstream	KCSAN: data-race in ext4_alloc_da_blocks / ext4_da_reserve_space	2	625d	642d	0/22	closed as invalid on 2019/11/19 14:44
upstream	KCSAN: data-race in ext4_alloc_da_blocks / ext4_da_reserve_space (3)	2	421d	440d	0/22	closed as invalid on 2020/06/18 14:24
upstream	KCSAN: data-race in ext4_alloc_da_blocks / ext4_da_reserve_space (5)	1	197d	197d	0/22	auto-closed as invalid on 2021/02/16 17:07
upstream	KCSAN: data-race in ext4_alloc_da_blocks / ext4_da_reserve_space (2)	7	531d	596d	0/22	auto-closed as invalid on 2020/04/23 17:25

Sample crash report:

==================================================================
BUG: KCSAN: data-race in ext4_alloc_da_blocks / ext4_da_reserve_space

write to 0xffff88811ec09808 of 4 bytes by task 23147 on cpu 0:
 ext4_da_reserve_space+0x12b/0x220 fs/ext4/inode.c:1475
 ext4_insert_delayed_block fs/ext4/inode.c:1640 [inline]
 ext4_da_map_blocks fs/ext4/inode.c:1754 [inline]
 ext4_da_get_block_prep+0x4d5/0x990 fs/ext4/inode.c:1818
 ext4_block_write_begin+0x433/0xb60 fs/ext4/inode.c:1060
 ext4_da_write_begin+0x507/0xad0 fs/ext4/inode.c:2996
 generic_perform_write+0x196/0x390 mm/filemap.c:3505
 ext4_buffered_write_iter+0x2cc/0x3b0 fs/ext4/file.c:269
 ext4_file_write_iter+0x768/0x1060 include/linux/fs.h:784
 call_write_iter include/linux/fs.h:1882 [inline]
 do_iter_readv_writev+0x32e/0x3d0 fs/read_write.c:721
 do_iter_write+0x112/0x4b0 fs/read_write.c:1026
 vfs_iter_write+0x4c/0x70 fs/read_write.c:1067
 iter_file_splice_write+0x41a/0x770 fs/splice.c:750
 do_splice_from fs/splice.c:846 [inline]
 direct_splice_actor+0x95/0x160 fs/splice.c:1016
 splice_direct_to_actor+0x365/0x660 fs/splice.c:971
 do_splice_direct+0xf2/0x170 fs/splice.c:1059
 do_sendfile+0x56a/0xba0 fs/read_write.c:1548
 __do_sys_sendfile64 fs/read_write.c:1609 [inline]
 __se_sys_sendfile64 fs/read_write.c:1595 [inline]
 __x64_sys_sendfile64+0xf2/0x130 fs/read_write.c:1595
 do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff88811ec09808 of 4 bytes by task 23145 on cpu 1:
 ext4_alloc_da_blocks+0x1f/0x130 fs/ext4/inode.c:3111
 ext4_release_file+0x5b/0x1c0 fs/ext4/file.c:142
 __fput+0x246/0x4d0 fs/file_table.c:281
 ____fput+0x11/0x20 fs/file_table.c:314
 task_work_run+0x8e/0x110 kernel/task_work.c:141
 tracehook_notify_resume include/linux/tracehook.h:188 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:165 [inline]
 exit_to_user_mode_prepare+0x1b2/0x210 kernel/entry/common.c:192
 syscall_exit_to_user_mode+0x16/0x30 kernel/entry/common.c:267
 do_syscall_64+0x45/0x80 arch/x86/entry/common.c:56
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 23145 Comm: syz-executor.1 Not tainted 5.9.0-rc7-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================

Crashes (10):
Manager	Time	Kernel	Commit	Syzkaller	Config	Log	Report	VM info
ci2-upstream-kcsan-gce	2020/10/03 06:53	upstream	d3d45f8220d6	2653fa43	.config	log	report	info
ci2-upstream-kcsan-gce	2020/09/29 20:36	upstream	fb0155a09b02	5abc3f1a	.config	log	report	info
ci2-upstream-kcsan-gce	2020/09/06 21:45	upstream	dd9fb9bb3340	abf9ba4f	.config	log	report
ci2-upstream-kcsan-gce	2020/08/26 22:18	upstream	2ac69819ba9e	318430cb	.config	log	report
ci2-upstream-kcsan-gce	2020/08/21 20:30	upstream	cd02217a5d81	6436ce4b	.config	log	report
ci2-upstream-kcsan-gce	2020/08/21 07:37	upstream	da2968ff879b	1d75fe45	.config	log	report
ci2-upstream-kcsan-gce	2020/07/31 13:20	upstream	d8b9faec54ae	8df85ed9	.config	log	report
ci2-upstream-kcsan-gce	2020/07/11 06:20	upstream	a581387e415b	18d18b59	.config	log	report
ci2-upstream-kcsan-gce	2020/07/08 20:47	upstream	63e1968a2c87	9f9845eb	.config	log	report
ci2-upstream-kcsan-gce	2020/06/24 22:47	upstream	26e122e97a3d	9d60b18e	.config	log	report