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KCSAN: data-race in ext4_handle_inode_extension / ext4_mpage_readpages (3)

Status: auto-closed as invalid on 2021/05/17 11:16
Subsystems: ext4
[Documentation on labels]
First crash: 1575d, last: 1559d
Similar bugs (2)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KCSAN: data-race in ext4_handle_inode_extension / ext4_mpage_readpages (2) ext4 6 14 1654d 1683d 0/29 auto-closed as invalid on 2021/02/09 13:32
upstream KCSAN: data-race in ext4_handle_inode_extension / ext4_mpage_readpages ext4 6 4 1864d 1909d 0/29 closed as invalid on 2020/06/18 14:24

Sample crash report:
==================================================================
BUG: KCSAN: data-race in ext4_handle_inode_extension / ext4_mpage_readpages

write to 0xffff8881074b9670 of 8 bytes by task 31548 on cpu 0:
 i_size_write include/linux/fs.h:872 [inline]
 ext4_update_inode_size fs/ext4/ext4.h:3292 [inline]
 ext4_handle_inode_extension+0x226/0x550 fs/ext4/file.c:331
 ext4_dio_write_iter fs/ext4/file.c:557 [inline]
 ext4_file_write_iter+0xef4/0x10b0 fs/ext4/file.c:661
 call_write_iter include/linux/fs.h:1977 [inline]
 do_iter_readv_writev+0x2cb/0x360 fs/read_write.c:740
 do_iter_write+0x112/0x4c0 fs/read_write.c:866
 vfs_iter_write+0x4c/0x70 fs/read_write.c:907
 iter_file_splice_write+0x40a/0x750 fs/splice.c:689
 do_splice_from fs/splice.c:767 [inline]
 direct_splice_actor+0x80/0xa0 fs/splice.c:936
 splice_direct_to_actor+0x345/0x650 fs/splice.c:891
 do_splice_direct+0xf5/0x170 fs/splice.c:979
 do_sendfile+0x7a6/0xe20 fs/read_write.c:1260
 __do_sys_sendfile64 fs/read_write.c:1325 [inline]
 __se_sys_sendfile64 fs/read_write.c:1311 [inline]
 __x64_sys_sendfile64+0xf2/0x130 fs/read_write.c:1311
 do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xae

read to 0xffff8881074b9670 of 8 bytes by task 31555 on cpu 1:
 ext4_readpage_limit fs/ext4/readpage.c:219 [inline]
 ext4_mpage_readpages+0x44b/0x1550 fs/ext4/readpage.c:265
 ext4_readahead+0x99/0xa0 fs/ext4/inode.c:3262
 read_pages+0x9c/0x6e0 mm/readahead.c:130
 page_cache_ra_unbounded+0x17d/0x4c0 mm/readahead.c:212
 ondemand_readahead+0x560/0x780 mm/readahead.c:267
 page_cache_sync_ra+0x18f/0x1a0 mm/readahead.c:577
 page_cache_sync_readahead include/linux/pagemap.h:840 [inline]
 filemap_get_pages+0x1ba/0x660 mm/filemap.c:2375
 filemap_read+0x1ba/0x7b0 mm/filemap.c:2458
 generic_file_read_iter+0x82/0x410 mm/filemap.c:2609
 ext4_file_read_iter+0x2e0/0x420 fs/ext4/file.c:74
 call_read_iter include/linux/fs.h:1971 [inline]
 generic_file_splice_read+0x22a/0x310 fs/splice.c:311
 do_splice_to fs/splice.c:796 [inline]
 splice_direct_to_actor+0x2aa/0x650 fs/splice.c:870
 do_splice_direct+0xf5/0x170 fs/splice.c:979
 do_sendfile+0x7a6/0xe20 fs/read_write.c:1260
 __do_sys_sendfile64 fs/read_write.c:1319 [inline]
 __se_sys_sendfile64 fs/read_write.c:1311 [inline]
 __x64_sys_sendfile64+0xa9/0x130 fs/read_write.c:1311
 do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xae

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 31555 Comm: syz-executor.0 Tainted: G        W         5.12.0-rc6-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================

Crashes (2):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2021/04/10 15:38 upstream d4961772226d 6a81331a .config console log report info ci2-upstream-kcsan-gce KCSAN: data-race in ext4_handle_inode_extension / ext4_mpage_readpages
2021/03/25 11:04 upstream e138138003eb 6a383ecf .config console log report info ci2-upstream-kcsan-gce KCSAN: data-race in ext4_handle_inode_extension / ext4_mpage_readpages
* Struck through repros no longer work on HEAD.