On Mon, Feb 12, 2018 at 4:54 PM, syzbot <syzbot+a2a3c4909716e271487e@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote: > Hello, > > syzbot hit the following crash on upstream commit > f1517df8701c9f12dae9ce7f43a5d300a6917619 (Thu Feb 8 23:18:32 2018 +0000) > Merge tag 'nfsd-4.16' of git://linux-nfs.org/~bfields/linux > > So far this crash happened 3 times on upstream. > C reproducer is attached. > syzkaller reproducer is attached. > Raw console output is attached. > compiler: gcc (GCC) 7.1.1 20170620 > .config is attached. > user-space arch: i386 This seems to be binder, so +binder maintainers. > IMPORTANT: if you fix the bug, please add the following tag to the commit: > Reported-by: syzbot+a2a3c4909716e271487e@xxxxxxxxxxxxxxxxxxxxxxxxx > It will help syzbot understand when the bug is fixed. See footer for > details. > If you forward the report, please keep this part and the footer. > > ================================================================== > BUG: KASAN: use-after-free in debug_spin_lock_before > kernel/locking/spinlock_debug.c:83 [inline] > BUG: KASAN: use-after-free in do_raw_spin_lock+0x1e0/0x220 > kernel/locking/spinlock_debug.c:112 > Read of size 4 at addr ffff8801db1608a4 by task syzkaller818560/5118 > > CPU: 1 PID: 5118 Comm: syzkaller818560 Not tainted 4.15.0+ #215 > 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+0x194/0x257 lib/dump_stack.c:53 > print_address_description+0x73/0x250 mm/kasan/report.c:256 > kasan_report_error mm/kasan/report.c:354 [inline] > kasan_report+0x23b/0x360 mm/kasan/report.c:412 > __asan_report_load4_noabort+0x14/0x20 mm/kasan/report.c:432 > debug_spin_lock_before kernel/locking/spinlock_debug.c:83 [inline] > do_raw_spin_lock+0x1e0/0x220 kernel/locking/spinlock_debug.c:112 > __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:117 [inline] > _raw_spin_lock_irqsave+0x9e/0xc0 kernel/locking/spinlock.c:152 > remove_wait_queue+0x81/0x350 kernel/sched/wait.c:50 > ep_remove_wait_queue fs/eventpoll.c:595 [inline] > ep_unregister_pollwait.isra.7+0x18c/0x590 fs/eventpoll.c:613 > ep_free+0x13f/0x320 fs/eventpoll.c:830 > ep_eventpoll_release+0x44/0x60 fs/eventpoll.c:862 > __fput+0x327/0x7e0 fs/file_table.c:209 > ____fput+0x15/0x20 fs/file_table.c:243 > task_work_run+0x199/0x270 kernel/task_work.c:113 > tracehook_notify_resume include/linux/tracehook.h:191 [inline] > exit_to_usermode_loop+0x275/0x2f0 arch/x86/entry/common.c:166 > prepare_exit_to_usermode arch/x86/entry/common.c:196 [inline] > syscall_return_slowpath arch/x86/entry/common.c:265 [inline] > do_syscall_32_irqs_on arch/x86/entry/common.c:336 [inline] > do_fast_syscall_32+0xbe8/0xfa1 arch/x86/entry/common.c:392 > entry_SYSENTER_compat+0x54/0x63 arch/x86/entry/entry_64_compat.S:129 > RIP: 0023:0xf7f56c79 > RSP: 002b:00000000f7f3112c EFLAGS: 00000286 ORIG_RAX: 000000000000014a > RAX: 0000000000000009 RBX: 0000000000000008 RCX: 0000000000000009 > RDX: 0000000000000000 RSI: 00000000000000f0 RDI: 0000000008120030 > RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 > R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 > R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 > > Allocated by task 5105: > save_stack+0x43/0xd0 mm/kasan/kasan.c:447 > set_track mm/kasan/kasan.c:459 [inline] > kasan_kmalloc+0xad/0xe0 mm/kasan/kasan.c:552 > kmem_cache_alloc_trace+0x136/0x740 mm/slab.c:3607 > kmalloc include/linux/slab.h:512 [inline] > kzalloc include/linux/slab.h:701 [inline] > binder_get_thread+0x1cf/0x870 drivers/android/binder.c:4279 > binder_poll+0x8c/0x390 drivers/android/binder.c:4393 > ep_item_poll.isra.10+0xf2/0x320 fs/eventpoll.c:885 > ep_insert+0x6a2/0x1ac0 fs/eventpoll.c:1457 > SYSC_epoll_ctl fs/eventpoll.c:2104 [inline] > SyS_epoll_ctl+0x12bf/0x1a80 fs/eventpoll.c:1990 > do_syscall_32_irqs_on arch/x86/entry/common.c:330 [inline] > do_fast_syscall_32+0x3ee/0xfa1 arch/x86/entry/common.c:392 > entry_SYSENTER_compat+0x54/0x63 arch/x86/entry/entry_64_compat.S:129 > > Freed by task 5105: > save_stack+0x43/0xd0 mm/kasan/kasan.c:447 > set_track mm/kasan/kasan.c:459 [inline] > __kasan_slab_free+0x11a/0x170 mm/kasan/kasan.c:520 > kasan_slab_free+0xe/0x10 mm/kasan/kasan.c:527 > __cache_free mm/slab.c:3485 [inline] > kfree+0xd9/0x260 mm/slab.c:3800 > binder_free_thread drivers/android/binder.c:4306 [inline] > binder_thread_dec_tmpref+0x27f/0x310 drivers/android/binder.c:1879 > binder_thread_release+0x4a1/0x6b0 drivers/android/binder.c:4382 > binder_ioctl+0xc02/0x1417 drivers/android/binder.c:4599 > C_SYSC_ioctl fs/compat_ioctl.c:1461 [inline] > compat_SyS_ioctl+0x151/0x2a30 fs/compat_ioctl.c:1407 > do_syscall_32_irqs_on arch/x86/entry/common.c:330 [inline] > do_fast_syscall_32+0x3ee/0xfa1 arch/x86/entry/common.c:392 > entry_SYSENTER_compat+0x54/0x63 arch/x86/entry/entry_64_compat.S:129 > > The buggy address belongs to the object at ffff8801db160800 > which belongs to the cache kmalloc-512 of size 512 > The buggy address is located 164 bytes inside of > 512-byte region [ffff8801db160800, ffff8801db160a00) > The buggy address belongs to the page: > page:ffffea00076c5800 count:1 mapcount:0 mapping:ffff8801db160080 index:0x0 > flags: 0x2fffc0000000100(slab) > raw: 02fffc0000000100 ffff8801db160080 0000000000000000 0000000100000006 > raw: ffffea00073c6ea0 ffffea0007076ce0 ffff8801db000940 0000000000000000 > page dumped because: kasan: bad access detected > > Memory state around the buggy address: > ffff8801db160780: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc > ffff8801db160800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >> >> ffff8801db160880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb > > ^ > ffff8801db160900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb > ffff8801db160980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb > ================================================================== > > > --- > This bug is generated by a dumb bot. It may contain errors. > See https://goo.gl/tpsmEJ for details. > Direct all questions to syzkaller@xxxxxxxxxxxxxxxx. > > syzbot will keep track of this bug report. > If you forgot to add the Reported-by tag, once the fix for this bug is > merged > into any tree, please reply to this email with: > #syz fix: exact-commit-title > If you want to test a patch for this bug, please reply with: > #syz test: git://repo/address.git branch > and provide the patch inline or as an attachment. > To mark this as a duplicate of another syzbot report, please reply with: > #syz dup: exact-subject-of-another-report > If it's a one-off invalid bug report, please reply with: > #syz invalid > Note: if the crash happens again, it will cause creation of a new bug > report. > Note: all commands must start from beginning of the line in the email body. > > -- > 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/001a113f65b6d93e74056505e572%40google.com. > For more options, visit https://groups.google.com/d/optout.
