mmap: syz-executor.5 (14901) uses deprecated remap_file_pages() syscall. See Documentation/vm/remap_file_pages.rst.
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BUG: KCSAN: data-race in shmem_add_to_page_cache / shmem_recalc_inode

write to 0xffff8880a4bc2e60 of 8 bytes by task 14907 on cpu 1:
 shmem_add_to_page_cache+0x4b0/0x6c0 mm/shmem.c:643
 shmem_getpage_gfp+0x43f/0x14c0 mm/shmem.c:1876
 shmem_fault+0x117/0x480 mm/shmem.c:2067
 __do_fault+0xa8/0x1e0 mm/memory.c:3276
 do_shared_fault mm/memory.c:3728 [inline]
 do_fault mm/memory.c:3806 [inline]
 handle_pte_fault mm/memory.c:4033 [inline]
 __handle_mm_fault+0x1d2d/0x2cf0 mm/memory.c:4163
 handle_mm_fault+0x21c/0x540 mm/memory.c:4200
 do_user_addr_fault arch/x86/mm/fault.c:1442 [inline]
 do_page_fault+0x4a4/0xa52 arch/x86/mm/fault.c:1517
 page_fault+0x34/0x40 arch/x86/entry/entry_64.S:1203
 copy_user_enhanced_fast_string+0xe/0x30 arch/x86/lib/copy_user_64.S:204
 copy_user_generic arch/x86/include/asm/uaccess_64.h:37 [inline]
 raw_copy_to_user arch/x86/include/asm/uaccess_64.h:128 [inline]
 _copy_to_user+0xaa/0xb0 lib/usercopy.c:30
 copy_to_user include/linux/uaccess.h:152 [inline]
 extract_crng_user drivers/char/random.c:1056 [inline]
 urandom_read_nowarn.isra.0+0xa2/0x370 drivers/char/random.c:1807
 __do_sys_getrandom drivers/char/random.c:2004 [inline]
 __se_sys_getrandom drivers/char/random.c:1979 [inline]
 __x64_sys_getrandom+0xdb/0x150 drivers/char/random.c:1979
 do_syscall_64+0xc7/0x390 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff8880a4bc2e60 of 8 bytes by task 14901 on cpu 0:
 shmem_recalc_inode+0x50/0x180 mm/shmem.c:306
 shmem_getpage_gfp+0x5ca/0x14c0 mm/shmem.c:1890
 shmem_fault+0x117/0x480 mm/shmem.c:2067
 __do_fault+0xa8/0x1e0 mm/memory.c:3276
 do_read_fault mm/memory.c:3673 [inline]
 do_fault mm/memory.c:3802 [inline]
 handle_pte_fault mm/memory.c:4033 [inline]
 __handle_mm_fault+0x2611/0x2cf0 mm/memory.c:4163
 handle_mm_fault+0x21c/0x540 mm/memory.c:4200
 do_user_addr_fault arch/x86/mm/fault.c:1442 [inline]
 do_page_fault+0x4a4/0xa52 arch/x86/mm/fault.c:1517
 page_fault+0x34/0x40 arch/x86/entry/entry_64.S:1203
 fault_in_pages_readable include/linux/pagemap.h:600 [inline]
 iov_iter_fault_in_readable+0x22b/0x2c0 lib/iov_iter.c:431
 generic_perform_write+0xc6/0x320 mm/filemap.c:3277
 ext4_buffered_write_iter+0x14e/0x280 fs/ext4/file.c:270
 ext4_file_write_iter+0xf4/0xd30 fs/ext4/file.c:642
 call_write_iter include/linux/fs.h:1901 [inline]
 new_sync_write+0x303/0x400 fs/read_write.c:483
 __vfs_write+0x9e/0xb0 fs/read_write.c:496
 vfs_write fs/read_write.c:558 [inline]
 vfs_write+0x189/0x380 fs/read_write.c:542
 ksys_write+0xc5/0x1a0 fs/read_write.c:611
 __do_sys_write fs/read_write.c:623 [inline]
 __se_sys_write fs/read_write.c:620 [inline]
 __x64_sys_write+0x49/0x60 fs/read_write.c:620
 do_syscall_64+0xc7/0x390 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 14901 Comm: syz-executor.5 Not tainted 5.6.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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