[moderation] [pm?] KCSAN: data-race in __uart_start / __update_runtime_status

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 026e680b0a08 Merge tag 'pwm/for-6.9-rc3-fixes' of git://gi..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=16bc171d180000
kernel config: https://syzkaller.appspot.com/x/.config?x=d024e89f7bb376ce
dashboard link: https://syzkaller.appspot.com/bug?extid=d099b800e891fcd6f5fd
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
CC: [gre...@linuxfoundation.org len....@intel.com linux-...@vger.kernel.org linu...@vger.kernel.org pa...@ucw.cz raf...@kernel.org]

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/eb276a281ef9/disk-026e680b.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/e25825b48b7a/vmlinux-026e680b.xz
kernel image: https://storage.googleapis.com/syzbot-assets/376093368942/bzImage-026e680b.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+d099b8...@syzkaller.appspotmail.com

==================================================================
BUG: KCSAN: data-race in __uart_start / __update_runtime_status

write to 0xffff888100e709c4 of 4 bytes by task 3773 on cpu 0:
__update_runtime_status+0xef/0x1d0 drivers/base/power/runtime.c:98
rpm_resume+0x9f1/0xd00 drivers/base/power/runtime.c:921
pm_runtime_work+0xe4/0x130 drivers/base/power/runtime.c:979
process_one_work kernel/workqueue.c:3254 [inline]
process_scheduled_works+0x465/0x990 kernel/workqueue.c:3335
worker_thread+0x526/0x730 kernel/workqueue.c:3416
kthread+0x1d1/0x210 kernel/kthread.c:388
ret_from_fork+0x4b/0x60 arch/x86/kernel/process.c:147
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:243

read to 0xffff888100e709c4 of 4 bytes by task 4488 on cpu 1:
pm_runtime_active include/linux/pm_runtime.h:164 [inline]
__uart_start+0x1ab/0x270 drivers/tty/serial/serial_core.c:159
uart_write+0x348/0x450 drivers/tty/serial/serial_core.c:615
do_output_char+0x491/0x500 drivers/tty/n_tty.c:428
process_output drivers/tty/n_tty.c:494 [inline]
n_tty_write+0x8cc/0xb90 drivers/tty/n_tty.c:2390
iterate_tty_write drivers/tty/tty_io.c:1021 [inline]
file_tty_write+0x386/0x690 drivers/tty/tty_io.c:1096
tty_write+0x28/0x30 drivers/tty/tty_io.c:1117
call_write_iter include/linux/fs.h:2108 [inline]
iter_file_splice_write+0x5e6/0x970 fs/splice.c:743
do_splice_from fs/splice.c:941 [inline]
direct_splice_actor+0x16c/0x2c0 fs/splice.c:1164
splice_direct_to_actor+0x305/0x670 fs/splice.c:1108
do_splice_direct_actor fs/splice.c:1207 [inline]
do_splice_direct+0xd7/0x150 fs/splice.c:1233
do_sendfile+0x3b9/0x970 fs/read_write.c:1295
__do_sys_sendfile64 fs/read_write.c:1362 [inline]
__se_sys_sendfile64 fs/read_write.c:1348 [inline]
__x64_sys_sendfile64+0x110/0x150 fs/read_write.c:1348
do_syscall_64+0xd3/0x1d0
entry_SYSCALL_64_after_hwframe+0x72/0x7a

value changed: 0x00000001 -> 0x00000000

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 4488 Comm: syz-executor.2 Tainted: G W 6.9.0-rc2-syzkaller-00002-g026e680b0a08 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
==================================================================


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