On Mon, Feb 12, 2018 at 5:52 PM, Todd Kjos <tkjos@xxxxxxxxxx> wrote: > On Mon, Feb 12, 2018 at 7:57 AM, Dmitry Vyukov <dvyukov@xxxxxxxxxx> wrote: >> >> 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. > > > There's a fix queued for 4.16: https://patchwork.kernel.org/patch/10146253/ The commit on which it was triggered already includes this fix. So there must be another bug. >> > 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.
