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BUG: KCSAN: data-race in ext4_es_lookup_extent / ext4_es_lookup_extent

read to 0xffff888126b09c28 of 8 bytes by task 7363 on cpu 0:
 ext4_es_lookup_extent+0x3ba/0x510 fs/ext4/extents_status.c:950
 ext4_da_map_blocks fs/ext4/inode.c:1871 [inline]
 ext4_da_get_block_prep+0x159/0xa60 fs/ext4/inode.c:1992
 __block_write_begin_int+0x2ea/0xf10 fs/buffer.c:1968
 __block_write_begin fs/buffer.c:2018 [inline]
 block_page_mkwrite+0x19f/0x230 fs/buffer.c:2480
 ext4_page_mkwrite+0x5af/0xce0 fs/ext4/inode.c:6238
 do_page_mkwrite+0x8f/0x1a0 mm/memory.c:2199
 do_shared_fault mm/memory.c:3545 [inline]
 do_fault mm/memory.c:3613 [inline]
 handle_pte_fault mm/memory.c:3840 [inline]
 __handle_mm_fault+0x20ea/0x2d00 mm/memory.c:3964
 handle_mm_fault+0x21b/0x520 mm/memory.c:4001
 do_user_addr_fault arch/x86/mm/fault.c:1441 [inline]
 __do_page_fault+0x3fb/0x9e0 arch/x86/mm/fault.c:1506
 do_page_fault+0x54/0x233 arch/x86/mm/fault.c:1530
 page_fault+0x34/0x40 arch/x86/entry/entry_64.S:1202

write to 0xffff888126b09c28 of 8 bytes by task 7366 on cpu 1:
 ext4_es_lookup_extent+0x3d3/0x510 fs/ext4/extents_status.c:950
 ext4_map_blocks+0xc2/0xf70 fs/ext4/inode.c:530
 ext4_mpage_readpages+0x92b/0x1270 fs/ext4/readpage.c:182
 ext4_readpages+0x92/0xc0 fs/ext4/inode.c:3388
 read_pages+0xa2/0x2d0 mm/readahead.c:126
 __do_page_cache_readahead+0x353/0x390 mm/readahead.c:212
 ra_submit mm/internal.h:62 [inline]
 ondemand_readahead+0x35d/0x710 mm/readahead.c:492
 page_cache_async_readahead+0x22c/0x250 mm/readahead.c:574
 generic_file_buffered_read mm/filemap.c:2079 [inline]
 generic_file_read_iter+0xffc/0x1440 mm/filemap.c:2344
 ext4_file_read_iter fs/ext4/file.c:77 [inline]
 ext4_file_read_iter+0xfa/0x240 fs/ext4/file.c:65
 call_read_iter include/linux/fs.h:1864 [inline]
 generic_file_splice_read+0x35c/0x500 fs/splice.c:307
 do_splice_to+0xf2/0x130 fs/splice.c:877
 splice_direct_to_actor+0x1a1/0x510 fs/splice.c:954

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 7366 Comm: syz-executor.4 Not tainted 5.3.0+ #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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