syzbot

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BUG: KCSAN: data-race in next_uptodate_page / shmem_write_end

write to 0xffff88813011acd8 of 8 bytes by task 4416 on cpu 1:
 i_size_write include/linux/fs.h:888 [inline]
 shmem_write_end+0x9a/0x4a0 mm/shmem.c:2586
 generic_perform_write+0x253/0x3d0 mm/filemap.c:3937
 __generic_file_write_iter+0xe6/0x290 mm/filemap.c:4054
 generic_file_write_iter+0x7d/0x1c0 mm/filemap.c:4086
 do_iter_write+0x418/0x700 fs/read_write.c:861
 vfs_iter_write+0x50/0x70 fs/read_write.c:902
 iter_file_splice_write+0x456/0x7d0 fs/splice.c:778
 do_splice_from fs/splice.c:856 [inline]
 direct_splice_actor+0x84/0xa0 fs/splice.c:1023
 splice_direct_to_actor+0x2ee/0x5f0 fs/splice.c:978
 do_splice_direct+0x104/0x180 fs/splice.c:1066
 do_sendfile+0x3b8/0x950 fs/read_write.c:1255
 __do_sys_sendfile64 fs/read_write.c:1317 [inline]
 __se_sys_sendfile64 fs/read_write.c:1309 [inline]
 __x64_sys_sendfile64+0xbd/0x150 fs/read_write.c:1309
 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 0xffff88813011acd8 of 8 bytes by task 4424 on cpu 0:
 i_size_read include/linux/fs.h:866 [inline]
 next_uptodate_page+0x47b/0x560 mm/filemap.c:3457
 next_map_page mm/filemap.c:3482 [inline]
 filemap_map_pages+0x722/0x830 mm/filemap.c:3554
 do_fault_around mm/memory.c:4461 [inline]
 do_read_fault mm/memory.c:4487 [inline]
 do_fault mm/memory.c:4621 [inline]
 handle_pte_fault mm/memory.c:4909 [inline]
 __handle_mm_fault mm/memory.c:5051 [inline]
 handle_mm_fault+0xfc3/0x21d0 mm/memory.c:5197
 do_user_addr_fault arch/x86/mm/fault.c:1407 [inline]
 handle_page_fault arch/x86/mm/fault.c:1498 [inline]
 exc_page_fault+0x45f/0x640 arch/x86/mm/fault.c:1554
 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:570
 do_strnlen_user lib/strnlen_user.c:49 [inline]
 strnlen_user+0x105/0x1d0 lib/strnlen_user.c:113
 strndup_user+0x1f/0xa0 mm/util.c:247
 keyctl_pkey_params_get+0x63/0x310 security/keys/keyctl_pkey.c:89
 keyctl_pkey_params_get_2+0xd8/0x310 security/keys/keyctl_pkey.c:128
 keyctl_pkey_e_d_s+0x57/0x240 security/keys/keyctl_pkey.c:222
 __do_sys_keyctl security/keys/keyctl.c:1992 [inline]
 __se_sys_keyctl+0x595/0xbc0 security/keys/keyctl.c:1869
 __x64_sys_keyctl+0x67/0x80 security/keys/keyctl.c:1869
 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: 0x000000000000304e -> 0x0000000000003060

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 4424 Comm: syz-executor.2 Not tainted 6.2.0-syzkaller-12913-gae3419fbac84-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/16/2023
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