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BUG: KCSAN: data-race in __mod_timer / blk_add_timer

write to 0xffff8881020d0598 of 8 bytes by task 7981 on cpu 1:
 __mod_timer+0x720/0xc30 kernel/time/timer.c:1052
 mod_timer+0x1b/0x20 kernel/time/timer.c:1108
 blk_add_timer+0x18b/0x1a0 block/blk-timeout.c:164
 blk_mq_start_request+0xf8/0x280 block/blk-mq.c:1140
 loop_queue_rq+0x42/0x5c0 drivers/block/loop.c:1799
 __blk_mq_issue_directly+0x6f/0x420 block/blk-mq.c:2424
 __blk_mq_try_issue_directly+0x25d/0x2c0 block/blk-mq.c:2477
 blk_mq_try_issue_directly block/blk-mq.c:2501 [inline]
 blk_mq_submit_bio+0xb5a/0xff0 block/blk-mq.c:2852
 __submit_bio+0x151/0x350 block/blk-core.c:800
 __submit_bio_noacct_mq block/blk-core.c:875 [inline]
 submit_bio_noacct+0x418/0x4e0 block/blk-core.c:901
 submit_bio+0x10c/0x180
 submit_bh_wbc+0x2db/0x320 fs/buffer.c:3055
 submit_bh fs/buffer.c:3061 [inline]
 __bread_slow fs/buffer.c:1180 [inline]
 __bread_gfp+0x110/0x220 fs/buffer.c:1382
 sb_bread include/linux/buffer_head.h:303 [inline]
 fat_fill_super+0xece/0x2af0 fs/fat/inode.c:1647
 msdos_fill_super+0x29/0x30 fs/fat/namei_msdos.c:655
 mount_bdev+0x1e8/0x290 fs/super.c:1367
 msdos_mount+0x2d/0x40 fs/fat/namei_msdos.c:662
 legacy_get_tree+0x70/0xc0 fs/fs_context.c:610
 vfs_get_tree+0x4a/0x1a0 fs/super.c:1497
 do_new_mount fs/namespace.c:3024 [inline]
 path_mount+0x11cf/0x1c40 fs/namespace.c:3354
 do_mount fs/namespace.c:3367 [inline]
 __do_sys_mount fs/namespace.c:3575 [inline]
 __se_sys_mount+0x24b/0x2f0 fs/namespace.c:3552
 __x64_sys_mount+0x63/0x70 fs/namespace.c:3552
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x44/0xd0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

read to 0xffff8881020d0598 of 8 bytes by task 7982 on cpu 0:
 blk_add_timer+0x11f/0x1a0
 blk_mq_start_request+0xf8/0x280 block/blk-mq.c:1140
 loop_queue_rq+0x42/0x5c0 drivers/block/loop.c:1799
 __blk_mq_issue_directly+0x6f/0x420 block/blk-mq.c:2424
 __blk_mq_try_issue_directly+0x25d/0x2c0 block/blk-mq.c:2477
 blk_mq_request_issue_directly block/blk-mq.c:2511 [inline]
 blk_mq_plug_issue_direct+0x16d/0x5e0 block/blk-mq.c:2531
 blk_mq_flush_plug_list+0x2b7/0x6c0 block/blk-mq.c:2600
 blk_flush_plug+0x25a/0x2b0 block/blk-core.c:1276
 blk_finish_plug+0x44/0x60 block/blk-core.c:1300
 read_pages+0x34b/0x5f0 mm/readahead.c:149
 page_cache_ra_unbounded+0x3a6/0x400 mm/readahead.c:238
 do_page_cache_ra mm/readahead.c:268 [inline]
 force_page_cache_ra+0x1e6/0x220 mm/readahead.c:300
 page_cache_sync_ra+0xcc/0xe0 mm/readahead.c:574
 page_cache_sync_readahead include/linux/pagemap.h:1056 [inline]
 filemap_get_pages mm/filemap.c:2589 [inline]
 filemap_read+0x3ed/0x1430 mm/filemap.c:2676
 blkdev_read_iter+0x2cc/0x380 block/fops.c:616
 call_read_iter include/linux/fs.h:2068 [inline]
 new_sync_read fs/read_write.c:400 [inline]
 vfs_read+0x66c/0x750 fs/read_write.c:481
 ksys_read+0xd9/0x190 fs/read_write.c:619
 __do_sys_read fs/read_write.c:629 [inline]
 __se_sys_read fs/read_write.c:627 [inline]
 __x64_sys_read+0x3e/0x50 fs/read_write.c:627
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x44/0xd0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

value changed: 0x0000000100011260 -> 0x000000010001646d

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 7982 Comm: udevd Not tainted 5.17.0-rc8-syzkaller-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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