linux-kernel - [syzbot] [block?] KCSAN: data-race in __mod_timer / blk_add

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [day] [month] [year] [list]
Message-ID: <67973f6c.050a0220.2eae65.0045.GAE@google.com>
Date: Mon, 27 Jan 2025 00:10:20 -0800
From: syzbot <syzbot+87ab99ec8b81ae79bae2@...kaller.appspotmail.com>
To: axboe@...nel.dk, linux-block@...r.kernel.org, linux-kernel@...r.kernel.org, 
	syzkaller-bugs@...glegroups.com
Subject: [syzbot] [block?] KCSAN: data-race in __mod_timer / blk_add_timer (10)

Hello,

syzbot found the following issue on:

HEAD commit:    b9d8a295ed6b Merge tag 'x86_misc_for_v6.14_rc1' of git://g..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=165fe824580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=53a413b6b1edf42
dashboard link: https://syzkaller.appspot.com/bug?extid=87ab99ec8b81ae79bae2
compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/5cd1021b471b/disk-b9d8a295.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/034a042761ab/vmlinux-b9d8a295.xz
kernel image: https://storage.googleapis.com/syzbot-assets/3c985aefa760/bzImage-b9d8a295.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+87ab99ec8b81ae79bae2@...kaller.appspotmail.com

==================================================================
BUG: KCSAN: data-race in __mod_timer / blk_add_timer

write to 0xffff8881026b9c00 of 8 bytes by task 4008 on cpu 1:
 __mod_timer+0x578/0x7f0 kernel/time/timer.c:1172
 mod_timer+0x1f/0x30 kernel/time/timer.c:1241
 blk_add_timer+0x17e/0x190 block/blk-timeout.c:164
 blk_mq_start_request+0x185/0x3b0 block/blk-mq.c:1351
 scsi_queue_rq+0x14aa/0x1a10 drivers/scsi/scsi_lib.c:1846
 blk_mq_dispatch_rq_list+0x630/0xfa0 block/blk-mq.c:2120
 __blk_mq_do_dispatch_sched block/blk-mq-sched.c:170 [inline]
 blk_mq_do_dispatch_sched block/blk-mq-sched.c:184 [inline]
 __blk_mq_sched_dispatch_requests+0x604/0xd50 block/blk-mq-sched.c:309
 blk_mq_sched_dispatch_requests+0x88/0x120 block/blk-mq-sched.c:331
 blk_mq_run_hw_queue+0x18a/0x230 block/blk-mq.c:2354
 blk_mq_flush_plug_list+0xbd5/0xef0 block/blk-mq.c:2917
 __blk_flush_plug+0x216/0x290 block/blk-core.c:1214
 blk_finish_plug+0x48/0x70 block/blk-core.c:1241
 swap_cluster_readahead+0x342/0x3f0 mm/swap_state.c:698
 swapin_readahead+0xe4/0x6f0 mm/swap_state.c:882
 do_swap_page+0x31b/0x2550 mm/memory.c:4341
 handle_pte_fault mm/memory.c:5804 [inline]
 __handle_mm_fault mm/memory.c:5944 [inline]
 handle_mm_fault+0x8e4/0x2ac0 mm/memory.c:6112
 do_user_addr_fault arch/x86/mm/fault.c:1389 [inline]
 handle_page_fault arch/x86/mm/fault.c:1481 [inline]
 exc_page_fault+0x296/0x650 arch/x86/mm/fault.c:1539
 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623
 __get_user_8+0x18/0x30 arch/x86/lib/getuser.S:98
 fetch_robust_entry kernel/futex/core.c:762 [inline]
 exit_robust_list+0x31/0x280 kernel/futex/core.c:790
 futex_cleanup kernel/futex/core.c:1022 [inline]
 futex_exit_release+0xe3/0x130 kernel/futex/core.c:1123
 exit_mm_release+0x1a/0x30 kernel/fork.c:1655
 exit_mm+0x38/0x190 kernel/exit.c:543
 do_exit+0x559/0x17f0 kernel/exit.c:925
 do_group_exit+0x102/0x150 kernel/exit.c:1087
 get_signal+0xeb9/0x1000 kernel/signal.c:3036
 arch_do_signal_or_restart+0x95/0x4b0 arch/x86/kernel/signal.c:337
 exit_to_user_mode_loop kernel/entry/common.c:111 [inline]
 exit_to_user_mode_prepare include/linux/entry-common.h:329 [inline]
 __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline]
 syscall_exit_to_user_mode+0x62/0x120 kernel/entry/common.c:218
 do_syscall_64+0xd6/0x1c0 arch/x86/entry/common.c:89
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff8881026b9c00 of 8 bytes by task 4015 on cpu 0:
 blk_add_timer+0x112/0x190
 blk_mq_start_request+0x185/0x3b0 block/blk-mq.c:1351
 scsi_queue_rq+0x14aa/0x1a10 drivers/scsi/scsi_lib.c:1846
 blk_mq_dispatch_rq_list+0x630/0xfa0 block/blk-mq.c:2120
 __blk_mq_do_dispatch_sched block/blk-mq-sched.c:170 [inline]
 blk_mq_do_dispatch_sched block/blk-mq-sched.c:184 [inline]
 __blk_mq_sched_dispatch_requests+0x604/0xd50 block/blk-mq-sched.c:309
 blk_mq_sched_dispatch_requests+0x88/0x120 block/blk-mq-sched.c:331
 blk_mq_run_hw_queue+0x18a/0x230 block/blk-mq.c:2354
 blk_mq_flush_plug_list+0xbd5/0xef0 block/blk-mq.c:2917
 __blk_flush_plug+0x216/0x290 block/blk-core.c:1214
 blk_finish_plug+0x48/0x70 block/blk-core.c:1241
 swap_cluster_readahead+0x342/0x3f0 mm/swap_state.c:698
 swapin_readahead+0xe4/0x6f0 mm/swap_state.c:882
 do_swap_page+0x31b/0x2550 mm/memory.c:4341
 handle_pte_fault mm/memory.c:5804 [inline]
 __handle_mm_fault mm/memory.c:5944 [inline]
 handle_mm_fault+0x8e4/0x2ac0 mm/memory.c:6112
 do_user_addr_fault arch/x86/mm/fault.c:1389 [inline]
 handle_page_fault arch/x86/mm/fault.c:1481 [inline]
 exc_page_fault+0x296/0x650 arch/x86/mm/fault.c:1539
 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623
 __get_user_8+0x18/0x30 arch/x86/lib/getuser.S:98
 fetch_robust_entry kernel/futex/core.c:762 [inline]
 exit_robust_list+0x31/0x280 kernel/futex/core.c:790
 futex_cleanup kernel/futex/core.c:1022 [inline]
 futex_exit_release+0xe3/0x130 kernel/futex/core.c:1123
 exit_mm_release+0x1a/0x30 kernel/fork.c:1655
 exit_mm+0x38/0x190 kernel/exit.c:543
 do_exit+0x559/0x17f0 kernel/exit.c:925
 do_group_exit+0x102/0x150 kernel/exit.c:1087
 get_signal+0xeb9/0x1000 kernel/signal.c:3036
 arch_do_signal_or_restart+0x95/0x4b0 arch/x86/kernel/signal.c:337
 exit_to_user_mode_loop kernel/entry/common.c:111 [inline]
 exit_to_user_mode_prepare include/linux/entry-common.h:329 [inline]
 __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline]
 syscall_exit_to_user_mode+0x62/0x120 kernel/entry/common.c:218
 do_syscall_64+0xd6/0x1c0 arch/x86/entry/common.c:89
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x00000000ffff9e3f -> 0x00000000ffffa0d4

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 4015 Comm: syz.1.204 Not tainted 6.13.0-syzkaller-01005-gb9d8a295ed6b #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 12/27/2024
==================================================================


---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzkaller@...glegroups.com.

syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.

If the report is already addressed, let syzbot know by replying with:
#syz fix: exact-commit-title

If you want to overwrite report's subsystems, reply with:
#syz set subsystems: new-subsystem
(See the list of subsystem names on the web dashboard)

If the report is a duplicate of another one, reply with:
#syz dup: exact-subject-of-another-report

If you want to undo deduplication, reply with:
#syz undup