syz.5.1524: attempt to access beyond end of device
loop5: rw=2049, sector=1040, nr_sectors = 32 limit=512
syz.5.1524: attempt to access beyond end of device
loop5: rw=2049, sector=1104, nr_sectors = 32 limit=512
==================================================================
BUG: KCSAN: data-race in xas_clear_mark / xas_find_marked

read-write to 0xffff88811ad436c0 of 8 bytes by task 7870 on cpu 1:
 instrument_read_write include/linux/instrumented.h:56 [inline]
 __instrument_read_write_bitop include/asm-generic/bitops/instrumented-non-atomic.h:84 [inline]
 ___test_and_clear_bit include/asm-generic/bitops/instrumented-non-atomic.h:114 [inline]
 node_clear_mark lib/xarray.c:102 [inline]
 xas_clear_mark+0x91/0x180 lib/xarray.c:922
 __folio_start_writeback+0x257/0x350 mm/page-writeback.c:3034
 mpage_write_folio fs/mpage.c:620 [inline]
 __mpage_writepages+0xd92/0x1370 fs/mpage.c:686
 mpage_writepages include/linux/mpage.h:27 [inline]
 fat_writepages+0x26/0x30 fs/fat/inode.c:200
 do_writepages+0x1b9/0x300 mm/page-writeback.c:2571
 filemap_writeback mm/filemap.c:387 [inline]
 filemap_fdatawrite_range mm/filemap.c:412 [inline]
 filemap_write_and_wait_range+0x166/0x370 mm/filemap.c:684
 direct_write_fallback+0x73/0x100 fs/libfs.c:2099
 __generic_file_write_iter+0xfd/0x120 mm/filemap.c:4471
 generic_file_write_iter+0x77/0x1f0 mm/filemap.c:4501
 do_iter_readv_writev+0x4f6/0x5a0 fs/read_write.c:-1
 vfs_writev+0x2d1/0x8b0 fs/read_write.c:1058
 do_pwritev fs/read_write.c:1154 [inline]
 __do_sys_pwritev2 fs/read_write.c:1212 [inline]
 __se_sys_pwritev2+0xfc/0x1c0 fs/read_write.c:1203
 __x64_sys_pwritev2+0x67/0x80 fs/read_write.c:1203
 x64_sys_call+0xe07/0x3020 arch/x86/include/generated/asm/syscalls_64.h:329
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x136/0x3c0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff88811ad436c0 of 8 bytes by task 7874 on cpu 0:
 xas_find_chunk include/linux/xarray.h:1752 [inline]
 xas_find_marked+0x211/0x650 lib/xarray.c:1510
 find_get_entry mm/filemap.c:2081 [inline]
 filemap_get_folios_tag+0xf7/0x400 mm/filemap.c:2348
 writeback_get_folio mm/page-writeback.c:2428 [inline]
 writeback_iter+0x48f/0x7c0 mm/page-writeback.c:2529
 __mpage_writepages+0x76c/0x1370 fs/mpage.c:675
 mpage_writepages include/linux/mpage.h:27 [inline]
 fat_writepages+0x26/0x30 fs/fat/inode.c:200
 do_writepages+0x1b9/0x300 mm/page-writeback.c:2571
 filemap_writeback mm/filemap.c:387 [inline]
 filemap_fdatawrite_range mm/filemap.c:412 [inline]
 filemap_write_and_wait_range+0x166/0x370 mm/filemap.c:684
 kiocb_write_and_wait mm/filemap.c:2904 [inline]
 generic_file_read_iter+0xf4/0x320 mm/filemap.c:2978
 do_iter_readv_writev+0x4f6/0x5a0 fs/read_write.c:-1
 vfs_readv+0x1e8/0x6d0 fs/read_write.c:1019
 do_preadv fs/read_write.c:1133 [inline]
 __do_sys_preadv2 fs/read_write.c:1192 [inline]
 __se_sys_preadv2+0xfc/0x1c0 fs/read_write.c:1183
 __x64_sys_preadv2+0x67/0x80 fs/read_write.c:1183
 x64_sys_call+0x2b3b/0x3020 arch/x86/include/generated/asm/syscalls_64.h:328
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x136/0x3c0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x07ffffffe0000000 -> 0x07fffff800000000

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 7874 Comm: syz.5.1524 Tainted: G        W           syzkaller #0 PREEMPT(lazy) 
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
==================================================================