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BUG: KCSAN: data-race in detach_if_pending / wbt_wait

read to 0xffff888129143b98 of 8 bytes by task 9594 on cpu 1:
 blk_stat_is_active block/blk-stat.h:131 [inline]
 wbt_wait+0x177/0x250 block/blk-wbt.c:593
 __rq_qos_throttle+0x47/0x70 block/blk-rq-qos.c:72
 rq_qos_throttle block/blk-rq-qos.h:182 [inline]
 blk_mq_make_request+0x29c/0xf60 block/blk-mq.c:1932
 generic_make_request block/blk-core.c:1066 [inline]
 generic_make_request+0x196/0x700 block/blk-core.c:1008
 submit_bio+0x96/0x3c0 block/blk-core.c:1192
 submit_bh_wbc+0x40f/0x460 fs/buffer.c:3135
 submit_bh fs/buffer.c:3141 [inline]
 __sync_dirty_buffer+0xd3/0x210 fs/buffer.c:3227
 sync_dirty_buffer+0x24/0x40 fs/buffer.c:3240
 __ext4_handle_dirty_metadata+0x19c/0x3e0 fs/ext4/ext4_jbd2.c:316
 ext4_handle_dirty_dirblock+0x20a/0x280 fs/ext4/namei.c:404
 add_dirent_to_buf+0x271/0x390 fs/ext4/namei.c:2026
 ext4_add_entry+0x37b/0x8f0 fs/ext4/namei.c:2225
 ext4_add_nondir+0x61/0x190 fs/ext4/namei.c:2561
 ext4_symlink+0x629/0x9b0 fs/ext4/namei.c:3344
 vfs_symlink fs/namei.c:4131 [inline]
 vfs_symlink+0x218/0x310 fs/namei.c:4117
 do_symlinkat+0x1a5/0x1e0 fs/namei.c:4158
 __do_sys_symlink fs/namei.c:4177 [inline]
 __se_sys_symlink fs/namei.c:4175 [inline]
 __x64_sys_symlink+0x3f/0x50 fs/namei.c:4175
 do_syscall_64+0xcc/0x3a0 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

write to 0xffff888129143b98 of 8 bytes by task 28686 on cpu 0:
 __hlist_del include/linux/list.h:764 [inline]
 detach_timer kernel/time/timer.c:815 [inline]
 detach_if_pending+0xcd/0x290 kernel/time/timer.c:832
 __mod_timer kernel/time/timer.c:1012 [inline]
 mod_timer+0x141/0x7a0 kernel/time/timer.c:1100
 sk_reset_timer+0x2d/0xd0 net/core/sock.c:2840
 inet_csk_reset_xmit_timer include/net/inet_connection_sock.h:234 [inline]
 tcp_reset_xmit_timer include/net/tcp.h:1296 [inline]
 tcp_rearm_rto net/ipv4/tcp_input.c:3011 [inline]
 tcp_rearm_rto+0x1e7/0x2a0 net/ipv4/tcp_input.c:2987
 tcp_event_new_data_sent+0x218/0x220 net/ipv4/tcp_output.c:77
 tcp_write_xmit+0xa97/0x3190 net/ipv4/tcp_output.c:2448
 __tcp_push_pending_frames+0x7b/0x1d0 net/ipv4/tcp_output.c:2617
 tcp_push+0x1f7/0x3e0 net/ipv4/tcp.c:726
 tcp_sendmsg_locked+0x1d71/0x2040 net/ipv4/tcp.c:1405
 tcp_sendmsg+0x39/0x60 net/ipv4/tcp.c:1436
 inet_sendmsg+0x6d/0x90 net/ipv4/af_inet.c:807
 sock_sendmsg_nosec net/socket.c:639 [inline]
 sock_sendmsg+0x9f/0xc0 net/socket.c:659
 sock_write_iter+0x16b/0x210 net/socket.c:991
 call_write_iter include/linux/fs.h:1902 [inline]
 new_sync_write+0x388/0x4a0 fs/read_write.c:483
 __vfs_write+0xb1/0xc0 fs/read_write.c:496
 vfs_write fs/read_write.c:558 [inline]
 vfs_write+0x18a/0x390 fs/read_write.c:542
 ksys_write+0x17b/0x1b0 fs/read_write.c:611
 __do_sys_write fs/read_write.c:623 [inline]
 __se_sys_write fs/read_write.c:620 [inline]
 __x64_sys_write+0x4c/0x60 fs/read_write.c:620
 do_syscall_64+0xcc/0x3a0 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 28686 Comm: syz-fuzzer Not tainted 5.5.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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