KCSAN: data-race in d_lru

Kernel	Title	Repro	Cause bisect	Fix bisect	Count	Last	Reported	Patched	Status
upstream	KCSAN: data-race in d_lru_del / dput fs				1	1630d	1629d	0/26	closed as invalid on 2019/11/19 14:04
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BUG: KCSAN: data-race in d_lru_del / dput

write to 0xffff8880b8591e40 of 4 bytes by task 9050 on cpu 1:
 d_lru_del+0x57/0xf0 fs/dcache.c:410
 select_collect+0x171/0x190 fs/dcache.c:1486
 d_walk+0x1b9/0x540 fs/dcache.c:1307
 shrink_dcache_parent+0xa9/0x2a0 fs/dcache.c:1546
 d_invalidate fs/dcache.c:1658 [inline]
 d_invalidate+0x87/0x170 fs/dcache.c:1643
 proc_invalidate_siblings_dcache+0x303/0x330 fs/proc/inode.c:149
 proc_flush_pid+0x20/0x30 fs/proc/base.c:3276
 release_task+0x94f/0xce0 kernel/exit.c:221
 wait_task_zombie kernel/exit.c:1078 [inline]
 wait_consider_task+0x1b43/0x1c60 kernel/exit.c:1305
 do_wait_thread kernel/exit.c:1368 [inline]
 do_wait+0x1c7/0x4c0 kernel/exit.c:1439
 kernel_wait4+0x146/0x230 kernel/exit.c:1611
 __do_sys_wait4+0xea/0x100 kernel/exit.c:1623
 __se_sys_wait4 kernel/exit.c:1619 [inline]
 __x64_sys_wait4+0x59/0x70 kernel/exit.c:1619
 do_syscall_64+0xc7/0x3b0 arch/x86/entry/common.c:295
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff8880b8591e40 of 4 bytes by task 10776 on cpu 0:
 fast_dput fs/dcache.c:727 [inline]
 dput+0x4b/0x700 fs/dcache.c:846
 proc_invalidate_siblings_dcache+0x30b/0x330 fs/proc/inode.c:150
 proc_flush_pid+0x20/0x30 fs/proc/base.c:3276
 release_task+0x94f/0xce0 kernel/exit.c:221
 exit_notify kernel/exit.c:677 [inline]
 do_exit+0x9a6/0x11e0 kernel/exit.c:816
 do_group_exit+0xae/0x1a0 kernel/exit.c:893
 get_signal+0x2a7/0x1290 kernel/signal.c:2739
 do_signal+0x2b/0x840 arch/x86/kernel/signal.c:784
 exit_to_usermode_loop+0x24a/0x2c0 arch/x86/entry/common.c:161
 prepare_exit_to_usermode arch/x86/entry/common.c:196 [inline]
 syscall_return_slowpath arch/x86/entry/common.c:279 [inline]
 do_syscall_64+0x38b/0x3b0 arch/x86/entry/common.c:305
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 10776 Comm: syz-executor.1 Not tainted 5.7.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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