syzbot

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BUG: KCSAN: data-race in bdev_set_nr_sectors / do_mpage_readpage

write to 0xffff8881004835f8 of 8 bytes by task 24492 on cpu 1:
 i_size_write include/linux/fs.h:901 [inline]
 bdev_set_nr_sectors+0x42/0x70 block/bdev.c:438
 set_capacity block/genhd.c:61 [inline]
 invalidate_disk+0x6c/0x80 block/genhd.c:736
 __loop_clr_fd+0x169/0x3b0 drivers/block/loop.c:1164
 loop_clr_fd drivers/block/loop.c:1257 [inline]
 lo_ioctl+0xe93/0x12e0 drivers/block/loop.c:1563
 blkdev_ioctl+0x375/0x460 block/ioctl.c:621
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:870 [inline]
 __se_sys_ioctl+0xcf/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 0xffff8881004835f8 of 8 bytes by task 24479 on cpu 0:
 i_size_read include/linux/fs.h:879 [inline]
 do_mpage_readpage+0x1b8/0xdf0 fs/mpage.c:194
 mpage_readahead+0x1b2/0x2d0 fs/mpage.c:382
 blkdev_readahead+0x1c/0x20 block/fops.c:401
 read_pages+0xa6/0x560 mm/readahead.c:160
 page_cache_ra_unbounded+0x2a9/0x2e0 mm/readahead.c:269
 do_page_cache_ra mm/readahead.c:299 [inline]
 page_cache_ra_order mm/readahead.c:559 [inline]
 ondemand_readahead+0x550/0x6c0 mm/readahead.c:681
 page_cache_async_ra+0x9d/0xb0 mm/readahead.c:730
 filemap_readahead mm/filemap.c:2538 [inline]
 filemap_get_pages+0x389/0xea0 mm/filemap.c:2579
 filemap_splice_read+0x23a/0x810 mm/filemap.c:2925
 vfs_splice_read fs/splice.c:996 [inline]
 splice_direct_to_actor+0x28c/0x690 fs/splice.c:1072
 do_splice_direct+0x10d/0x190 fs/splice.c:1197
 do_sendfile+0x3b6/0x9a0 fs/read_write.c:1254
 __do_sys_sendfile64 fs/read_write.c:1322 [inline]
 __se_sys_sendfile64 fs/read_write.c:1308 [inline]
 __x64_sys_sendfile64+0x110/0x150 fs/read_write.c:1308
 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: 0x0000000000279000 -> 0x0000000000000000

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 24479 Comm: syz-executor.3 Not tainted 6.5.0-rc4-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2023
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syz-executor.3: attempt to access beyond end of device
loop7: rw=524288, sector=256, nr_sectors = 256 limit=0