KCSAN: data-race in ext4_alloc_da_blocks / ext4_da_reserve

KCSAN: data-race in ext4_alloc_da_blocks / ext4_da_reserve_space
Status: closed as invalid on 2019/11/19 14:44
Reported-by: syzbot+@syzkaller.appspotmail.com
First crash: 703d, last: 687d

similar bugs (5):
Kernel	Title	Count	Last	Reported	Patched	Status
upstream	KCSAN: data-race in ext4_alloc_da_blocks / ext4_da_reserve_space (4)	10	360d	460d	0/22	auto-closed as invalid on 2020/11/07 06:53
upstream	KCSAN: data-race in ext4_alloc_da_blocks / ext4_da_reserve_space (3)	2	482d	502d	0/22	closed as invalid on 2020/06/18 14:24
upstream	KCSAN: data-race in ext4_alloc_da_blocks / ext4_da_reserve_space (6)	23	77d	221d	0/22	auto-closed as invalid on 2021/08/16 16:28
upstream	KCSAN: data-race in ext4_alloc_da_blocks / ext4_da_reserve_space (5)	1	258d	258d	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	592d	657d	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 0xffff888125e0e560 of 4 bytes by task 13970 on cpu 0:
 ext4_da_reserve_space+0x13f/0x280 fs/ext4/inode.c:1617
 ext4_insert_delayed_block fs/ext4/inode.c:1780 [inline]
 ext4_da_map_blocks fs/ext4/inode.c:1895 [inline]
 ext4_da_get_block_prep+0x87f/0xa60 fs/ext4/inode.c:1959
 ext4_block_write_begin+0x33e/0xba0 fs/ext4/inode.c:1202
 ext4_da_write_begin+0x1da/0x7e0 fs/ext4/inode.c:3094
 generic_perform_write+0x136/0x320 mm/filemap.c:3305
 __generic_file_write_iter+0x251/0x380 mm/filemap.c:3434
 ext4_file_write_iter+0x1bd/0xa00 fs/ext4/file.c:268
 call_write_iter include/linux/fs.h:1895 [inline]
 aio_write+0x1de/0x2d0 fs/aio.c:1583
 __io_submit_one fs/aio.c:1815 [inline]
 io_submit_one+0x639/0xe70 fs/aio.c:1862
 __do_sys_io_submit fs/aio.c:1921 [inline]
 __se_sys_io_submit fs/aio.c:1891 [inline]
 __x64_sys_io_submit+0x104/0x2d0 fs/aio.c:1891
 do_syscall_64+0xcc/0x370 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff888125e0e560 of 4 bytes by task 13960 on cpu 1:
 ext4_alloc_da_blocks+0x4b/0x180 fs/ext4/inode.c:3209
 ext4_release_file+0x10d/0x200 fs/ext4/file.c:88
 __fput+0x1e1/0x520 fs/file_table.c:280
 ____fput+0x1f/0x30 fs/file_table.c:313
 task_work_run+0xf6/0x130 kernel/task_work.c:113
 tracehook_notify_resume include/linux/tracehook.h:188 [inline]
 exit_to_usermode_loop+0x2b4/0x2c0 arch/x86/entry/common.c:163
 prepare_exit_to_usermode arch/x86/entry/common.c:194 [inline]
 syscall_return_slowpath arch/x86/entry/common.c:274 [inline]
 do_syscall_64+0x353/0x370 arch/x86/entry/common.c:300
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 13960 Comm: syz-executor.2 Not tainted 5.4.0-rc6+ #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================

Crashes (2):
Manager	Time	Kernel	Commit	Syzkaller	Config	Log	Report	Syz repro	C repro	VM info	Title
ci2-upstream-kcsan-gce	2019/11/11 07:12	https://github.com/google/ktsan.git kcsan	94c006602e13	dc438b91	.config	log	report
ci2-upstream-kcsan-gce	2019/10/25 11:24	https://github.com/google/ktsan.git kcsan	05f2236801fe	d01bb02a	.config	log	report