syzbot

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BUG: KCSAN: data-race in __lru_add_drain_all / folio_activate

read-write to 0xffff888237c28df8 of 1 bytes by task 5190 on cpu 0:
 folio_batch_add include/linux/pagevec.h:129 [inline]
 folio_batch_add_and_move mm/swap.c:261 [inline]
 folio_activate+0xd2/0x1d0 mm/swap.c:391
 folio_mark_accessed+0x137/0x1a0 mm/swap.c:511
 shmem_file_read_iter+0x2f3/0x570 mm/shmem.c:2671
 call_read_iter include/linux/fs.h:2183 [inline]
 new_sync_read fs/read_write.c:389 [inline]
 vfs_read+0x39a/0x560 fs/read_write.c:470
 ksys_read+0xeb/0x1a0 fs/read_write.c:613
 __do_sys_read fs/read_write.c:623 [inline]
 __se_sys_read fs/read_write.c:621 [inline]
 __x64_sys_read+0x42/0x50 fs/read_write.c:621
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

read to 0xffff888237c28df8 of 1 bytes by task 9172 on cpu 1:
 folio_batch_count include/linux/pagevec.h:108 [inline]
 cpu_needs_drain mm/swap.c:834 [inline]
 __lru_add_drain_all+0x20d/0x3c0 mm/swap.c:923
 lru_add_drain_all+0x10/0x20 mm/swap.c:939
 invalidate_bdev block/bdev.c:86 [inline]
 __invalidate_device+0x9c/0xc0 block/bdev.c:1017
 disk_force_media_change+0x116/0x180 block/disk-events.c:310
 __loop_clr_fd+0x245/0x3b0 drivers/block/loop.c:1174
 loop_clr_fd drivers/block/loop.c:1257 [inline]
 lo_ioctl+0xe9e/0x12f0 drivers/block/loop.c:1563
 blkdev_ioctl+0x3a4/0x490 block/ioctl.c:616
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:870 [inline]
 __se_sys_ioctl+0xc9/0x140 fs/ioctl.c:856
 __x64_sys_ioctl+0x43/0x50 fs/ioctl.c:856
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

value changed: 0x00 -> 0x01

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 9172 Comm: syz-executor.2 Not tainted 6.2.0-rc7-syzkaller-00216-gf339c2597ebb-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/21/2023
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