On Tue, 25 Apr 2023 at 10:05, syzbot <syzbot+e1786f049e71693263bf@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote: > > Hello, > > syzbot found the following issue on: > > HEAD commit: 1a0beef98b58 Merge tag 'tpmdd-v6.4-rc1' of git://git.kerne.. > git tree: upstream > console output: https://syzkaller.appspot.com/x/log.txt?x=1485f1dbc80000 > kernel config: https://syzkaller.appspot.com/x/.config?x=501f7c86f7a05a13 > dashboard link: https://syzkaller.appspot.com/bug?extid=e1786f049e71693263bf > compiler: Debian clang version 15.0.7, GNU ld (GNU Binutils for Debian) 2.35.2 > > Unfortunately, I don't have any reproducer for this issue yet. > > Downloadable assets: > disk image: https://storage.googleapis.com/syzbot-assets/f06c11683242/disk-1a0beef9.raw.xz > vmlinux: https://storage.googleapis.com/syzbot-assets/5c0a1cd5a059/vmlinux-1a0beef9.xz > kernel image: https://storage.googleapis.com/syzbot-assets/e4c318183ce3/bzImage-1a0beef9.xz > > IMPORTANT: if you fix the issue, please add the following tag to the commit: > Reported-by: syzbot+e1786f049e71693263bf@xxxxxxxxxxxxxxxxxxxxxxxxx op->currframe and probably other op fields are concurrently read/modified by both bcm_tx_setup() and bcm_can_tx(). If I am reading the code correctly, it can lead to a wide range of misbehavior, e.g. sending wrong/uninit data, reading/writing data out-of-bounds, etc. I think these functions need to be somehow serialized (stopping timers before doing any modifications to op?). > ================================================================== > BUG: KCSAN: data-race in bcm_can_tx / bcm_tx_setup > > write to 0xffff888137fcff10 of 4 bytes by task 10792 on cpu 0: > bcm_tx_setup+0x698/0xd30 net/can/bcm.c:995 > bcm_sendmsg+0x38b/0x470 net/can/bcm.c:1355 > sock_sendmsg_nosec net/socket.c:724 [inline] > sock_sendmsg net/socket.c:747 [inline] > ____sys_sendmsg+0x375/0x4c0 net/socket.c:2501 > ___sys_sendmsg net/socket.c:2555 [inline] > __sys_sendmsg+0x1e3/0x270 net/socket.c:2584 > __do_sys_sendmsg net/socket.c:2593 [inline] > __se_sys_sendmsg net/socket.c:2591 [inline] > __x64_sys_sendmsg+0x46/0x50 net/socket.c:2591 > do_syscall_x64 arch/x86/entry/common.c:50 [inline] > do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80 > entry_SYSCALL_64_after_hwframe+0x63/0xcd > > write to 0xffff888137fcff10 of 4 bytes by interrupt on cpu 1: > bcm_can_tx+0x38a/0x410 > bcm_tx_timeout_handler+0xdb/0x260 > __run_hrtimer kernel/time/hrtimer.c:1685 [inline] > __hrtimer_run_queues+0x217/0x700 kernel/time/hrtimer.c:1749 > hrtimer_run_softirq+0xd6/0x120 kernel/time/hrtimer.c:1766 > __do_softirq+0xc1/0x265 kernel/softirq.c:571 > invoke_softirq kernel/softirq.c:445 [inline] > __irq_exit_rcu+0x57/0xa0 kernel/softirq.c:650 > sysvec_apic_timer_interrupt+0x6d/0x80 arch/x86/kernel/apic/apic.c:1107 > asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:645 > kcsan_setup_watchpoint+0x3fe/0x410 kernel/kcsan/core.c:696 > string_nocheck lib/vsprintf.c:648 [inline] > string+0x16c/0x200 lib/vsprintf.c:726 > vsnprintf+0xa09/0xe20 lib/vsprintf.c:2796 > add_uevent_var+0xf0/0x1c0 lib/kobject_uevent.c:665 > kobject_uevent_env+0x225/0x5b0 lib/kobject_uevent.c:539 > kobject_uevent+0x1c/0x20 lib/kobject_uevent.c:642 > __loop_clr_fd+0x1e0/0x3b0 drivers/block/loop.c:1167 > lo_release+0xe4/0xf0 drivers/block/loop.c:1745 > blkdev_put+0x3fb/0x470 > kill_block_super+0x83/0xa0 fs/super.c:1410 > deactivate_locked_super+0x6b/0xd0 fs/super.c:331 > deactivate_super+0x9b/0xb0 fs/super.c:362 > cleanup_mnt+0x272/0x2e0 fs/namespace.c:1177 > __cleanup_mnt+0x19/0x20 fs/namespace.c:1184 > task_work_run+0x123/0x160 kernel/task_work.c:179 > resume_user_mode_work include/linux/resume_user_mode.h:49 [inline] > exit_to_user_mode_loop+0xd1/0xe0 kernel/entry/common.c:171 > exit_to_user_mode_prepare+0x6c/0xb0 kernel/entry/common.c:204 > __syscall_exit_to_user_mode_work kernel/entry/common.c:286 [inline] > syscall_exit_to_user_mode+0x26/0x140 kernel/entry/common.c:297 > do_syscall_64+0x4d/0xc0 arch/x86/entry/common.c:86 > entry_SYSCALL_64_after_hwframe+0x63/0xcd > > value changed: 0x00000059 -> 0x00000000 > > Reported by Kernel Concurrency Sanitizer on: > CPU: 1 PID: 3096 Comm: syz-executor.5 Not tainted 6.3.0-syzkaller-00113-g1a0beef98b58 #0 > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/14/2023 > ================================================================== > > > --- > 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@xxxxxxxxxxxxxxxx. > > syzbot will keep track of this issue. See: > https://goo.gl/tpsmEJ#status for how to communicate with syzbot. > > -- > You received this message because you are subscribed to the Google Groups "syzkaller-bugs" group. > To unsubscribe from this group and stop receiving emails from it, send an email to syzkaller-bugs+unsubscribe@xxxxxxxxxxxxxxxx. > To view this discussion on the web visit https://groups.google.com/d/msgid/syzkaller-bugs/00000000000059e1b705fa2494e4%40google.com.
