KCSAN: data-race in generic_file_buffered_read / ondemand

KCSAN: data-race in generic_file_buffered_read / ondemand_readahead
Status: auto-closed as invalid on 2021/02/20 07:23
Reported-by: syzbot+f1bfafb19b14137af422@syzkaller.appspotmail.com
First crash: 393d, last: 201d

Sample crash report:

==================================================================
BUG: KCSAN: data-race in generic_file_buffered_read / ondemand_readahead

write to 0xffff88810ad15db0 of 8 bytes by task 24342 on cpu 1:
 generic_file_buffered_read+0x64c/0x9a0 mm/filemap.c:2540
 generic_file_read_iter+0x80/0x3d0 mm/filemap.c:2633
 call_read_iter include/linux/fs.h:1895 [inline]
 generic_file_splice_read+0x22a/0x310 fs/splice.c:311
 do_splice_to fs/splice.c:788 [inline]
 splice_direct_to_actor+0x2aa/0x650 fs/splice.c:867
 do_splice_direct+0xf5/0x170 fs/splice.c:976
 do_sendfile+0x5db/0xca0 fs/read_write.c:1257
 __do_sys_sendfile64 fs/read_write.c:1318 [inline]
 __se_sys_sendfile64 fs/read_write.c:1304 [inline]
 __x64_sys_sendfile64+0xf2/0x130 fs/read_write.c:1304
 do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff88810ad15db0 of 8 bytes by task 24332 on cpu 0:
 ondemand_readahead+0x578/0x780 mm/readahead.c:506
 page_cache_sync_ra+0x1ab/0x1c0 mm/readahead.c:577
 page_cache_sync_readahead include/linux/pagemap.h:839 [inline]
 generic_file_buffered_read_get_pages+0x234/0xaf0 mm/filemap.c:2361
 generic_file_buffered_read+0x27f/0x9a0 mm/filemap.c:2481
 generic_file_read_iter+0x80/0x3d0 mm/filemap.c:2633
 call_read_iter include/linux/fs.h:1895 [inline]
 generic_file_splice_read+0x22a/0x310 fs/splice.c:311
 do_splice_to fs/splice.c:788 [inline]
 splice_direct_to_actor+0x2aa/0x650 fs/splice.c:867
 do_splice_direct+0xf5/0x170 fs/splice.c:976
 do_sendfile+0x5db/0xca0 fs/read_write.c:1257
 __do_sys_sendfile64 fs/read_write.c:1318 [inline]
 __se_sys_sendfile64 fs/read_write.c:1304 [inline]
 __x64_sys_sendfile64+0xf2/0x130 fs/read_write.c:1304
 do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 24332 Comm: syz-executor.1 Not tainted 5.11.0-rc3-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================

Crashes (34):
Manager	Time	Kernel	Commit	Syzkaller	Config	Log	Report	VM info
ci2-upstream-kcsan-gce	2021/01/16 07:22	upstream	1d94330a437a	65a7a854	.config	log	report	info
ci2-upstream-kcsan-gce	2020/12/28 18:31	upstream	5c8fe583cce5	8259d56c	.config	log	report	info
ci2-upstream-kcsan-gce	2020/12/26 15:33	upstream	40f78232f973	821e0b09	.config	log	report	info
ci2-upstream-kcsan-gce	2020/12/09 12:36	upstream	a68a0262abda	99917735	.config	log	report	info
ci2-upstream-kcsan-gce	2020/12/08 21:26	upstream	cd796ed33450	40cc414d	.config	log	report	info
ci2-upstream-kcsan-gce	2020/11/30 22:14	upstream	b65054597872	76831598	.config	log	report	info
ci2-upstream-kcsan-gce	2020/11/11 00:17	upstream	eccc87672492	cca87986	.config	log	report	info
ci2-upstream-kcsan-gce	2020/11/04 02:37	upstream	4ef8451b3326	cba33199	.config	log	report	info
ci2-upstream-kcsan-gce	2020/11/03 10:27	upstream	b7cbaf59f62f	cba33199	.config	log	report	info
ci2-upstream-kcsan-gce	2020/10/29 07:50	upstream	23859ae44402	f24824d3	.config	log	report	info
ci2-upstream-kcsan-gce	2020/10/16 10:50	upstream	9ff9b0d392ea	6e262c73	.config	log	report	info
ci2-upstream-kcsan-gce	2020/10/10 23:06	upstream	6f2f486d57c4	4a77ae0b	.config	log	report	info
ci2-upstream-kcsan-gce	2020/10/08 21:52	upstream	3d006ee42dde	92390980	.config	log	report	info
ci2-upstream-kcsan-gce	2020/09/23 08:06	upstream	805c6d3c1921	287cd75a	.config	log	report	info
ci2-upstream-kcsan-gce	2020/09/17 18:31	upstream	5925fa68fe82	8247808b	.config	log	report	info
ci2-upstream-kcsan-gce	2020/09/16 22:47	upstream	5925fa68fe82	77507d02	.config	log	report	info
ci2-upstream-kcsan-gce	2020/09/11 10:15	upstream	581cb3a26baf	adfb8b4e	.config	log	report
ci2-upstream-kcsan-gce	2020/09/05 19:18	upstream	9322c47b21b9	abf9ba4f	.config	log	report
ci2-upstream-kcsan-gce	2020/08/26 12:45	upstream	2ac69819ba9e	318430cb	.config	log	report
ci2-upstream-kcsan-gce	2020/08/19 12:57	upstream	18445bf405cb	db787902	.config	log	report
ci2-upstream-kcsan-gce	2020/08/16 21:45	upstream	2cc3c4b3c2e9	5ce13532	.config	log	report
ci2-upstream-kcsan-gce	2020/08/15 18:20	upstream	410520d07f5c	5ce13532	.config	log	report
ci2-upstream-kcsan-gce	2020/08/12 13:19	upstream	fb893de323e2	0d7bd2e0	.config	log	report
ci2-upstream-kcsan-gce	2020/08/12 01:03	upstream	bb5baaa9238e	bb3e5fe6	.config	log	report
ci2-upstream-kcsan-gce	2020/08/01 19:01	upstream	d52daa8620c6	8df85ed9	.config	log	report
ci2-upstream-kcsan-gce	2020/07/31 12:32	upstream	d8b9faec54ae	8df85ed9	.config	log	report
ci2-upstream-kcsan-gce	2020/07/30 19:29	upstream	83bdc7275e62	b0947553	.config	log	report
ci2-upstream-kcsan-gce	2020/07/30 18:56	upstream	83bdc7275e62	b0947553	.config	log	report
ci2-upstream-kcsan-gce	2020/07/29 02:32	upstream	6ba1b005ffc3	cb93dc6a	.config	log	report
ci2-upstream-kcsan-gce	2020/07/23 13:49	upstream	d15be546031c	340ea530	.config	log	report
ci2-upstream-kcsan-gce	2020/07/22 15:55	upstream	4fa640dc5230	128cd85f	.config	log	report
ci2-upstream-kcsan-gce	2020/07/21 14:34	upstream	4fa640dc5230	e562dd8a	.config	log	report
ci2-upstream-kcsan-gce	2020/07/21 02:19	upstream	4fa640dc5230	d88894e6	.config	log	report
ci2-upstream-kcsan-gce	2020/07/07 14:06	upstream	bfe91da29bfa	42723355	.config	log	report