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BUG: KCSAN: data-race in __percpu_counter_compare / percpu_counter_add_batch

read-write to 0xffff888101075e50 of 8 bytes by task 7466 on cpu 0:
 percpu_counter_add_batch+0x9a/0x110 lib/percpu_counter.c:91
 percpu_counter_add include/linux/percpu_counter.h:56 [inline]
 shmem_inode_acct_block mm/shmem.c:222 [inline]
 shmem_alloc_and_acct_page+0x188/0x580 mm/shmem.c:1573
 shmem_getpage_gfp+0x300/0x16c0 mm/shmem.c:1874
 shmem_getpage mm/shmem.c:149 [inline]
 shmem_write_begin+0x84/0x110 mm/shmem.c:2446
 generic_perform_write+0x1d6/0x3f0 mm/filemap.c:3787
 __generic_file_write_iter+0xe3/0x280 mm/filemap.c:3915
 generic_file_write_iter+0x75/0x130 mm/filemap.c:3947
 call_write_iter include/linux/fs.h:2050 [inline]
 new_sync_write fs/read_write.c:504 [inline]
 vfs_write+0x71c/0x890 fs/read_write.c:591
 ksys_write+0xe8/0x1a0 fs/read_write.c:644
 __do_sys_write fs/read_write.c:656 [inline]
 __se_sys_write fs/read_write.c:653 [inline]
 __x64_sys_write+0x3e/0x50 fs/read_write.c:653
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x2b/0x70 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

read to 0xffff888101075e50 of 8 bytes by task 7458 on cpu 1:
 percpu_counter_read include/linux/percpu_counter.h:72 [inline]
 __percpu_counter_compare+0x27/0x1a0 lib/percpu_counter.c:225
 percpu_counter_compare include/linux/percpu_counter.h:51 [inline]
 shmem_inode_acct_block mm/shmem.c:219 [inline]
 shmem_alloc_and_acct_page+0x115/0x580 mm/shmem.c:1573
 shmem_getpage_gfp+0x300/0x16c0 mm/shmem.c:1874
 shmem_getpage mm/shmem.c:149 [inline]
 shmem_write_begin+0x84/0x110 mm/shmem.c:2446
 generic_perform_write+0x1d6/0x3f0 mm/filemap.c:3787
 __generic_file_write_iter+0xe3/0x280 mm/filemap.c:3915
 generic_file_write_iter+0x75/0x130 mm/filemap.c:3947
 call_write_iter include/linux/fs.h:2050 [inline]
 new_sync_write fs/read_write.c:504 [inline]
 vfs_write+0x71c/0x890 fs/read_write.c:591
 ksys_write+0xe8/0x1a0 fs/read_write.c:644
 __do_sys_write fs/read_write.c:656 [inline]
 __se_sys_write fs/read_write.c:653 [inline]
 __x64_sys_write+0x3e/0x50 fs/read_write.c:653
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x2b/0x70 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

value changed: 0x0000000000001c20 -> 0x0000000000001c40

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 7458 Comm: syz-executor.4 Not tainted 5.18.0-rc3-syzkaller-00016-gb253435746d9-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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