L1TF CPU bug present and SMT on, data leak possible. See CVE-2018-3646 and https://www.kernel.org/doc/html/latest/admin-guide/hw-vuln/l1tf.html for details. BUG: sleeping function called from invalid context at mm/slab.h:419 in_atomic(): 1, irqs_disabled(): 1, pid: 9801, name: syz-executor.3 3 locks held by syz-executor.3/9801: #0: (&ep->mtx){+.+.}, at: [] SYSC_epoll_ctl fs/eventpoll.c:2080 [inline] #0: (&ep->mtx){+.+.}, at: [] SyS_epoll_ctl+0x516/0x2780 fs/eventpoll.c:2002 #1: (&dev->dev_mutex){+.+.}, at: [] v4l2_m2m_fop_poll+0x91/0x110 drivers/media/v4l2-core/v4l2-mem2mem.c:802 #2: (&(&q->done_lock)->rlock){....}, at: [] v4l2_m2m_poll+0x116/0x670 drivers/media/v4l2-core/v4l2-mem2mem.c:536 irq event stamp: 266 hardirqs last enabled at (265): [] __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:160 [inline] hardirqs last enabled at (265): [] _raw_spin_unlock_irqrestore+0x79/0xe0 kernel/locking/spinlock.c:192 hardirqs last disabled at (266): [] __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:108 [inline] hardirqs last disabled at (266): [] _raw_spin_lock_irqsave+0x66/0xc0 kernel/locking/spinlock.c:160 softirqs last enabled at (0): [] copy_process.part.0+0x12d0/0x71c0 kernel/fork.c:1734 softirqs last disabled at (0): [< (null)>] (null) Preemption disabled at: [< (null)>] (null) CPU: 1 PID: 9801 Comm: syz-executor.3 Not tainted 4.14.260-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0x1b2/0x281 lib/dump_stack.c:58 ___might_sleep.cold+0x235/0x250 kernel/sched/core.c:6041 slab_pre_alloc_hook mm/slab.h:419 [inline] slab_alloc mm/slab.c:3376 [inline] kmem_cache_alloc+0x284/0x3c0 mm/slab.c:3550 ep_ptable_queue_proc+0x9e/0x370 fs/eventpoll.c:1255 poll_wait include/linux/poll.h:50 [inline] v4l2_m2m_poll+0x583/0x670 drivers/media/v4l2-core/v4l2-mem2mem.c:538 v4l2_m2m_fop_poll+0xa4/0x110 drivers/media/v4l2-core/v4l2-mem2mem.c:804 v4l2_poll+0x133/0x1d0 drivers/media/v4l2-core/v4l2-dev.c:342 ep_item_poll fs/eventpoll.c:885 [inline] ep_insert fs/eventpoll.c:1490 [inline] SYSC_epoll_ctl fs/eventpoll.c:2117 [inline] SyS_epoll_ctl+0x14af/0x2780 fs/eventpoll.c:2002 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x46/0xbb RIP: 0033:0x7fb60cea2e99 RSP: 002b:00007fb60b818168 EFLAGS: 00000246 ORIG_RAX: 00000000000000e9 RAX: ffffffffffffffda RBX: 00007fb60cfb5f60 RCX: 00007fb60cea2e99 RDX: 0000000000000003 RSI: 0000000000000001 RDI: 0000000000000004 RBP: 00007fb60cefcff1 R08: 0000000000000000 R09: 0000000000000000 R10: 00000000200000c0 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ffcfe8c943f R14: 00007fb60b818300 R15: 0000000000022000 EXT4-fs (loop4): mounted filesystem without journal. Opts: ,errors=continue audit: type=1800 audit(1641347237.925:2): pid=9805 uid=0 auid=4294967295 ses=4294967295 op="collect_data" cause="failed(directio)" comm="syz-executor.4" name="bus" dev="sda1" ino=13942 res=0 audit: type=1800 audit(1641347240.755:3): pid=9868 uid=0 auid=4294967295 ses=4294967295 op="collect_data" cause="failed(directio)" comm="syz-executor.3" name="bus" dev="loop3" ino=4 res=0 audit: type=1800 audit(1641347243.536:4): pid=9906 uid=0 auid=4294967295 ses=4294967295 op="collect_data" cause="failed(directio)" comm="syz-executor.3" name="bus" dev="loop3" ino=6 res=0 audit: type=1800 audit(1641347244.506:5): pid=9930 uid=0 auid=4294967295 ses=4294967295 op="collect_data" cause="failed(directio)" comm="syz-executor.3" name="bus" dev="loop3" ino=8 res=0 unregister_netdevice: waiting for ip6gre0 to become free. Usage count = -1 audit: type=1800 audit(1641347246.576:6): pid=9962 uid=0 auid=4294967295 ses=4294967295 op="collect_data" cause="failed(directio)" comm="syz-executor.3" name="bus" dev="loop3" ino=10 res=0 ================================================================== BUG: KASAN: use-after-free in __lock_acquire+0x2c57/0x3f20 kernel/locking/lockdep.c:3369 Read of size 8 at addr ffff8880b60fcba0 by task kworker/u4:5/7949 CPU: 0 PID: 7949 Comm: kworker/u4:5 Tainted: G W 4.14.260-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: tipc_rcv tipc_recv_work Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0x1b2/0x281 lib/dump_stack.c:58 print_address_description.cold+0x54/0x1d3 mm/kasan/report.c:252 kasan_report_error.cold+0x8a/0x191 mm/kasan/report.c:351 kasan_report mm/kasan/report.c:409 [inline] __asan_report_load8_noabort+0x68/0x70 mm/kasan/report.c:430 __lock_acquire+0x2c57/0x3f20 kernel/locking/lockdep.c:3369 lock_acquire+0x170/0x3f0 kernel/locking/lockdep.c:3998 __raw_spin_lock_bh include/linux/spinlock_api_smp.h:135 [inline] _raw_spin_lock_bh+0x2f/0x40 kernel/locking/spinlock.c:176 spin_lock_bh include/linux/spinlock.h:322 [inline] tipc_subscrp_subscribe net/tipc/subscr.c:299 [inline] tipc_subscrb_rcv_cb+0x4d4/0xa40 net/tipc/subscr.c:338 tipc_receive_from_sock+0x25c/0x450 net/tipc/server.c:273 tipc_recv_work+0x75/0xd0 net/tipc/server.c:547 process_one_work+0x793/0x14a0 kernel/workqueue.c:2117 worker_thread+0x5cc/0xff0 kernel/workqueue.c:2251 kthread+0x30d/0x420 kernel/kthread.c:232 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404 Allocated by task 7949: save_stack mm/kasan/kasan.c:447 [inline] set_track mm/kasan/kasan.c:459 [inline] kasan_kmalloc+0xeb/0x160 mm/kasan/kasan.c:551 kmem_cache_alloc_trace+0x131/0x3d0 mm/slab.c:3618 kmalloc include/linux/slab.h:488 [inline] kzalloc include/linux/slab.h:661 [inline] tipc_subscrb_create net/tipc/subscr.c:223 [inline] tipc_subscrb_connect_cb+0x40/0x150 net/tipc/subscr.c:344 tipc_accept_from_sock+0x25b/0x400 net/tipc/server.c:313 tipc_recv_work+0x75/0xd0 net/tipc/server.c:547 process_one_work+0x793/0x14a0 kernel/workqueue.c:2117 worker_thread+0x5cc/0xff0 kernel/workqueue.c:2251 kthread+0x30d/0x420 kernel/kthread.c:232 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404 Freed by task 355: save_stack mm/kasan/kasan.c:447 [inline] set_track mm/kasan/kasan.c:459 [inline] kasan_slab_free+0xc3/0x1a0 mm/kasan/kasan.c:524 __cache_free mm/slab.c:3496 [inline] kfree+0xc9/0x250 mm/slab.c:3815 tipc_subscrb_kref_release net/tipc/subscr.c:155 [inline] kref_put include/linux/kref.h:70 [inline] tipc_subscrb_put+0x22/0x30 net/tipc/subscr.c:160 tipc_close_conn+0x16a/0x200 net/tipc/server.c:203 tipc_send_to_sock net/tipc/server.c:538 [inline] tipc_send_work+0x41e/0x520 net/tipc/server.c:564 process_one_work+0x793/0x14a0 kernel/workqueue.c:2117 worker_thread+0x5cc/0xff0 kernel/workqueue.c:2251 kthread+0x30d/0x420 kernel/kthread.c:232 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404 The buggy address belongs to the object at ffff8880b60fcb80 which belongs to the cache kmalloc-96 of size 96 The buggy address is located 32 bytes inside of 96-byte region [ffff8880b60fcb80, ffff8880b60fcbe0) The buggy address belongs to the page: page:ffffea0002d83f00 count:1 mapcount:0 mapping:ffff8880b60fc000 index:0xffff8880b60fc800 flags: 0xfff00000000100(slab) raw: 00fff00000000100 ffff8880b60fc000 ffff8880b60fc800 0000000100000008 raw: ffffea0002c7a7e0 ffffea00026f13a0 ffff88813fe744c0 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: