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BUG: KCSAN: data-race in blk_mq_get_request / blk_mq_get_request

write to 0xffff888129b97d48 of 8 bytes by task 27133 on cpu 0:
 blk_mq_get_request+0x91a/0xba0 block/blk-mq.c:396
 blk_mq_make_request+0x2d7/0xf60 block/blk-mq.c:2001
 generic_make_request block/blk-core.c:1075 [inline]
 generic_make_request+0x196/0x700 block/blk-core.c:1017
 submit_bio+0x8f/0x3a0 block/blk-core.c:1200
 submit_bh_wbc+0x40d/0x460 fs/buffer.c:3063
 submit_bh fs/buffer.c:3069 [inline]
 __sync_dirty_buffer+0xd9/0x210 fs/buffer.c:3155
 sync_dirty_buffer+0x21/0x30 fs/buffer.c:3168
 __ext4_handle_dirty_metadata+0x1b5/0x3d0 fs/ext4/ext4_jbd2.c:339
 ext4_handle_dirty_dirblock+0x206/0x270 fs/ext4/namei.c:411
 add_dirent_to_buf+0x271/0x3d0 fs/ext4/namei.c:2033
 ext4_add_entry+0x37c/0x970 fs/ext4/namei.c:2241
 ext4_add_nondir+0x59/0x170 fs/ext4/namei.c:2577
 ext4_create+0x168/0x300 fs/ext4/namei.c:2622
 lookup_open fs/namei.c:3081 [inline]
 open_last_lookups fs/namei.c:3155 [inline]
 path_openat+0x1f95/0x23d0 fs/namei.c:3343
 do_filp_open+0x11e/0x1b0 fs/namei.c:3373
 do_sys_openat2+0x52e/0x680 fs/open.c:1148
 do_sys_open+0xa2/0x110 fs/open.c:1164
 ksys_open include/linux/syscalls.h:1386 [inline]
 __do_sys_creat fs/open.c:1232 [inline]
 __se_sys_creat fs/open.c:1230 [inline]
 __x64_sys_creat+0x42/0x60 fs/open.c:1230
 do_syscall_64+0xc7/0x3b0 arch/x86/entry/common.c:295
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff888129b97d48 of 8 bytes by task 8577 on cpu 1:
 blk_mq_get_request+0x907/0xba0 block/blk-mq.c:396
 blk_mq_make_request+0x2d7/0xf60 block/blk-mq.c:2001
 generic_make_request block/blk-core.c:1075 [inline]
 generic_make_request+0x196/0x700 block/blk-core.c:1017
 submit_bio+0x8f/0x3a0 block/blk-core.c:1200
 ext4_io_submit+0xdf/0x110 fs/ext4/page-io.c:382
 ext4_writepages+0x5bb/0x1e10 fs/ext4/inode.c:2727
 do_writepages+0x6b/0x170 mm/page-writeback.c:2344
 __filemap_fdatawrite_range+0x1bb/0x220 mm/filemap.c:421
 file_write_and_wait_range+0xfb/0x160 mm/filemap.c:760
 ext4_sync_file+0x26e/0x8b0 fs/ext4/fsync.c:153
 vfs_fsync_range+0x7c/0x150 fs/sync.c:197
 generic_write_sync include/linux/fs.h:2872 [inline]
 ext4_buffered_write_iter+0x211/0x280 fs/ext4/file.c:277
 ext4_file_write_iter+0xf4/0xd30 fs/ext4/file.c:642
 call_write_iter include/linux/fs.h:1907 [inline]
 new_sync_write+0x303/0x400 fs/read_write.c:484
 __vfs_write+0x9e/0xb0 fs/read_write.c:497
 vfs_write fs/read_write.c:559 [inline]
 vfs_write+0x189/0x380 fs/read_write.c:543
 ksys_write+0xc5/0x1a0 fs/read_write.c:612
 __do_sys_write fs/read_write.c:624 [inline]
 __se_sys_write fs/read_write.c:621 [inline]
 __x64_sys_write+0x49/0x60 fs/read_write.c:621
 do_syscall_64+0xc7/0x3b0 arch/x86/entry/common.c:295
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 8577 Comm: rs:main Q:Reg Not tainted 5.7.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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