More KCSAN data-race Reports

From: Hao Sun
Date: Sat Apr 10 2021 - 23:42:30 EST


Hi

Since the last KCSAN report[1], I found two more KCSAN reports that
Syzbot had not reported.
Not sure if they are valid bugs, I hope the stack information in
reports can help you locate the problem.
Kernel config can be found in the attachment.

Here is the detailed information:
commit: 3b9cdafb5358eb9f3790de2f728f765fef100731
version: linux 5.11
git tree: upstream

Report-1
==================================================================
BUG: KCSAN: data-race in ext4_mark_iloc_dirty / jbd2_journal_commit_transaction

read-write to 0xffff88804451d800 of 8 bytes by task 4821 on cpu 1:
jbd2_journal_commit_transaction+0x222/0x3200
kjournald2+0x253/0x470
kthread+0x1f0/0x220
ret_from_fork+0x1f/0x30

read to 0xffff88804451d800 of 8 bytes by task 8418 on cpu 0:
ext4_mark_iloc_dirty+0x14ec/0x16e0
__ext4_mark_inode_dirty+0x4d2/0x5d0
ext4_evict_inode+0xb9f/0xed0
evict+0x1a6/0x410
iput+0x3fc/0x510
do_unlinkat+0x2c9/0x4d0
__x64_sys_unlink+0x2c/0x30
do_syscall_64+0x39/0x80
entry_SYSCALL_64_after_hwframe+0x44/0xae

Report-2
==================================================================
BUG: KCSAN: data-race in __ext4_handle_dirty_metadata /
jbd2_journal_commit_transaction

read-write to 0xffff88800e142800 of 8 bytes by task 4823 on cpu 0:
jbd2_journal_commit_transaction+0x222/0x3200
kjournald2+0x253/0x470
kthread+0x1f0/0x220
ret_from_fork+0x1f/0x30

read to 0xffff88800e142800 of 8 bytes by task 7925 on cpu 1:
__ext4_handle_dirty_metadata+0x11a/0x590
ext4_mark_iloc_dirty+0x12dd/0x16e0
__ext4_mark_inode_dirty+0x4d2/0x5d0
ext4_dirty_inode+0x86/0xa0
__mark_inode_dirty+0x70/0x6b0
file_update_time+0x3ab/0x3f0
file_modified+0x62/0x80
ext4_buffered_write_iter+0x1f9/0x3d0
ext4_file_write_iter+0x45e/0x10d0
vfs_write+0x6db/0x7c0
ksys_write+0xce/0x180
__x64_sys_write+0x3e/0x50
do_syscall_64+0x39/0x80
entry_SYSCALL_64_after_hwframe+0x44/0xae


[1] https://lore.kernel.org/lkml/CACkBjsZW5Sp4jB51+C5mrMssgq73x8iEko_EV6CTXVvtVa7KPQ@xxxxxxxxxxxxxx/

Attachment: config
Description: Binary data