KCSAN: data-race in atime_needs_update / propagate_one (2)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 4429f14a Merge tag 'block-5.10-2020-11-07' of git://git.ke..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=124dbb46500000
kernel config: https://syzkaller.appspot.com/x/.config?x=76dfc991796328d4
dashboard link: https://syzkaller.appspot.com/bug?extid=e99c777b7159852f020e
compiler: clang version 12.0.0 (https://github.com/llvm/llvm-project.git 913f6005669cfb590c99865a90bc51ed0983d09d)
CC: [linux-...@vger.kernel.org linux-...@vger.kernel.org vi...@zeniv.linux.org.uk]

Unfortunately, I don't have any reproducer for this issue yet.

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+e99c77...@syzkaller.appspotmail.com

==================================================================
BUG: KCSAN: data-race in atime_needs_update / propagate_one

read-write to 0xffff88814418a370 of 4 bytes by task 8457 on cpu 0:
propagate_one+0x323/0x3f0 fs/pnode.c:267
propagate_mnt+0x2f8/0x650 fs/pnode.c:319
attach_recursive_mnt+0x4fb/0x1180 fs/namespace.c:2129
graft_tree fs/namespace.c:2237 [inline]
do_add_mount fs/namespace.c:2784 [inline]
do_new_mount_fc fs/namespace.c:2823 [inline]
do_new_mount fs/namespace.c:2877 [inline]
path_mount+0x1aed/0x1c10 fs/namespace.c:3205
do_mount fs/namespace.c:3218 [inline]
__do_sys_mount fs/namespace.c:3426 [inline]
__se_sys_mount+0x23d/0x2e0 fs/namespace.c:3403
__x64_sys_mount+0x63/0x70 fs/namespace.c:3403
do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff88814418a370 of 4 bytes by task 8445 on cpu 1:
relatime_need_update fs/inode.c:1720 [inline]
atime_needs_update+0x1b7/0x370 fs/inode.c:1815
touch_atime+0x53/0x1a0 fs/inode.c:1830
file_accessed include/linux/fs.h:2204 [inline]
generic_file_buffered_read+0x1a1c/0x2110 mm/filemap.c:2458
generic_file_read_iter+0x80/0x3d0 mm/filemap.c:2535
ext4_file_read_iter+0x2d0/0x420 fs/ext4/file.c:74
__kernel_read+0x307/0x560 fs/read_write.c:454
integrity_kernel_read+0x4c/0x70 security/integrity/iint.c:191
ima_calc_file_hash_tfm security/integrity/ima/ima_crypto.c:484 [inline]
ima_calc_file_shash security/integrity/ima/ima_crypto.c:515 [inline]
ima_calc_file_hash+0x9c7/0x1430 security/integrity/ima/ima_crypto.c:580
ima_collect_measurement+0x168/0x300 security/integrity/ima/ima_api.c:250
process_measurement+0x9f1/0x1050 security/integrity/ima/ima_main.c:330
ima_file_check+0x72/0xa0 security/integrity/ima/ima_main.c:498
do_open fs/namei.c:3254 [inline]
path_openat+0x1887/0x20a0 fs/namei.c:3369
do_filp_open+0xbd/0x1d0 fs/namei.c:3396
do_sys_openat2+0xa3/0x240 fs/open.c:1168
do_sys_open fs/open.c:1184 [inline]
__do_sys_openat fs/open.c:1200 [inline]
__se_sys_openat fs/open.c:1195 [inline]
__x64_sys_openat+0xef/0x110 fs/open.c:1195
do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 8445 Comm: syz-fuzzer Not tainted 5.10.0-rc2-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================


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[syzbot]

Auto-closing this bug as obsolete.
Crashes did not happen for a while, no reproducer and no activity.