KCSAN: data-race in ext4_ext_index_trans_blocks / ext4_ext_insert

KCSAN: data-race in ext4_ext_index_trans_blocks / ext4_ext_insert_extent (2)
Status: closed as invalid on 2020/06/18 14:13
Reported-by: syzbot+@syzkaller.appspotmail.com
First crash: 486d, last: 483d

similar bugs (4):
Kernel	Title	Count	Last	Reported	Patched	Status
upstream	KCSAN: data-race in ext4_ext_index_trans_blocks / ext4_ext_insert_extent (5)	3	163d	187d	0/22	auto-closed as invalid on 2021/05/20 02:45
upstream	KCSAN: data-race in ext4_ext_index_trans_blocks / ext4_ext_insert_extent (3)	3	359d	370d	0/22	auto-closed as invalid on 2020/11/05 15:13
upstream	KCSAN: data-race in ext4_ext_index_trans_blocks / ext4_ext_insert_extent (4)	2	236d	261d	0/22	auto-closed as invalid on 2021/03/08 22:40
upstream	KCSAN: data-race in ext4_ext_index_trans_blocks / ext4_ext_insert_extent	1	568d	568d	0/22	auto-closed as invalid on 2020/05/15 19:56

Sample crash report:

==================================================================
BUG: KCSAN: data-race in ext4_ext_index_trans_blocks / ext4_ext_insert_extent

write to 0xffff8880badb5b46 of 2 bytes by task 20419 on cpu 1:
 le16_add_cpu include/linux/byteorder/generic.h:146 [inline]
 ext4_ext_grow_indepth fs/ext4/extents.c:1321 [inline]
 ext4_ext_create_new_leaf fs/ext4/extents.c:1371 [inline]
 ext4_ext_insert_extent+0xee9/0x25f0 fs/ext4/extents.c:2044
 ext4_split_extent_at+0x350/0x910 fs/ext4/extents.c:3198
 ext4_force_split_extent_at fs/ext4/extents.c:301 [inline]
 ext4_swap_extents+0x61e/0xee0 fs/ext4/extents.c:5598
 move_extent_per_page fs/ext4/move_extent.c:360 [inline]
 ext4_move_extents+0x12b2/0x1c90 fs/ext4/move_extent.c:673
 ext4_ioctl+0x2bea/0x3340 fs/ext4/ioctl.c:980
 vfs_ioctl fs/ioctl.c:47 [inline]
 ksys_ioctl+0x101/0x150 fs/ioctl.c:763
 __do_sys_ioctl fs/ioctl.c:772 [inline]
 __se_sys_ioctl fs/ioctl.c:770 [inline]
 __x64_sys_ioctl+0x47/0x60 fs/ioctl.c:770
 do_syscall_64+0xc7/0x3b0 arch/x86/entry/common.c:295
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff8880badb5b46 of 2 bytes by task 20413 on cpu 0:
 ext_depth fs/ext4/ext4_extents.h:190 [inline]
 ext4_ext_index_trans_blocks+0x8d/0xc0 fs/ext4/extents.c:2346
 ext4_index_trans_blocks fs/ext4/inode.c:5496 [inline]
 ext4_meta_trans_blocks+0x86/0x190 fs/ext4/inode.c:5522
 ext4_da_writepages_trans_blocks fs/ext4/inode.c:2501 [inline]
 ext4_writepages+0xaa0/0x1e10 fs/ext4/inode.c:2749
 do_writepages+0x6b/0x170 mm/page-writeback.c:2344
 __filemap_fdatawrite_range+0x1bb/0x220 mm/filemap.c:421
 file_write_and_wait_range+0xfb/0x160 mm/filemap.c:760
 ext4_sync_file+0x26e/0x8b0 fs/ext4/fsync.c:153
 vfs_fsync_range+0x7c/0x150 fs/sync.c:197
 generic_write_sync include/linux/fs.h:2872 [inline]
 ext4_buffered_write_iter+0x211/0x280 fs/ext4/file.c:277
 ext4_file_write_iter+0xf4/0xd30 fs/ext4/file.c:642
 call_write_iter include/linux/fs.h:1907 [inline]
 new_sync_write+0x303/0x400 fs/read_write.c:484
 __vfs_write+0x9e/0xb0 fs/read_write.c:497
 vfs_write fs/read_write.c:559 [inline]
 vfs_write+0x189/0x380 fs/read_write.c:543
 ksys_write+0xc5/0x1a0 fs/read_write.c:612
 __do_sys_write fs/read_write.c:624 [inline]
 __se_sys_write fs/read_write.c:621 [inline]
 __x64_sys_write+0x49/0x60 fs/read_write.c:621
 do_syscall_64+0xc7/0x3b0 arch/x86/entry/common.c:295
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 20413 Comm: syz-executor.2 Not tainted 5.7.0-rc1-syzkaller #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	2020/05/30 02:43	https://github.com/google/ktsan.git kcsan	7c3cd68e5d38	954bd312	.config	log	report
ci2-upstream-kcsan-gce	2020/05/27 14:14	https://github.com/google/ktsan.git kcsan	7c3cd68e5d38	9072c126	.config	log	report