syzbot

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BUG: KCSAN: data-race in bdev_set_nr_sectors / force_page_cache_ra

write to 0xffff888102469b10 of 8 bytes by task 25920 on cpu 0:
 i_size_write include/linux/fs.h:905 [inline]
 bdev_set_nr_sectors+0x42/0x70 block/bdev.c:437
 set_capacity block/genhd.c:60 [inline]
 set_capacity_and_notify+0x6e/0x170 block/genhd.c:73
 loop_set_size drivers/block/loop.c:237 [inline]
 loop_set_status+0x397/0x550 drivers/block/loop.c:1303
 lo_ioctl+0x892/0x12e0
 blkdev_ioctl+0x38e/0x480 block/ioctl.c:615
 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

read to 0xffff888102469b10 of 8 bytes by task 25921 on cpu 1:
 i_size_read include/linux/fs.h:883 [inline]
 do_page_cache_ra mm/readahead.c:287 [inline]
 force_page_cache_ra+0x12c/0x1d0 mm/readahead.c:331
 force_page_cache_readahead mm/internal.h:124 [inline]
 generic_fadvise+0x2c4/0x460 mm/fadvise.c:107
 vfs_fadvise mm/fadvise.c:188 [inline]
 ksys_fadvise64_64 mm/fadvise.c:202 [inline]
 __do_sys_fadvise64 mm/fadvise.c:217 [inline]
 __se_sys_fadvise64 mm/fadvise.c:215 [inline]
 __x64_sys_fadvise64+0xc9/0x100 mm/fadvise.c:215
 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: 0x0000000000081800 -> 0x0000000000000000

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 25921 Comm: syz-executor.5 Not tainted 6.4.0-rc6-syzkaller-00026-gfb054096aea0 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/25/2023
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