On Wed, Nov 2, 2016 at 11:14 PM, Dmitry Vyukov <dvyu...@google.com> wrote: > Here we go. > > The following program triggers kernel BUG in htab_elem_free. > On commit 0c183d92b20b5c84ca655b45ef57b3318b83eb9e (Oct 31). > Run as "while true; do ./a.out; done". > > ------------[ cut here ]------------ > kernel BUG at mm/slub.c:3866! > invalid opcode: 0000 [#1] SMP KASAN > Modules linked in: > CPU: 1 PID: 1542 Comm: kworker/1:2 Not tainted 4.9.0-rc3+ #20 > Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011 > Workqueue: events bpf_map_free_deferred > task: ffff88003b9c0040 task.stack: ffff88003cb70000 > RIP: 0010:[<ffffffff814c9f00>] [<ffffffff814c9f00>] kfree+0x140/0x1a0 > RSP: 0018:ffff88003cb77c50 EFLAGS: 00010246 > RAX: ffffea0000fb0aa0 RBX: ffff88003ec2a1a8 RCX: 0000000000000000 > RDX: 0000000000000000 RSI: 1ffff10007b50401 RDI: ffff88003ec2a1a8 > RBP: ffff88003cb77c70 R08: 0000000000021800 R09: 0000000000000000 > R10: 0000000000000000 R11: 0000000000000000 R12: ffffea0000fb0a80 > R13: ffffffff81392bcb R14: 0000000000000000 R15: ffff88003ec2a1a8 > FS: 0000000000000000(0000) GS:ffff88003ed00000(0000) knlGS:0000000000000000 > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > CR2: 00000000205d7000 CR3: 0000000037d29000 CR4: 00000000000006e0 > Stack: > dffffc0000000000 ffff88003da82008 ffff88003b75bb88 0000000000000000 > ffff88003cb77ce0 ffffffff81392bcb ffffffff81acf4f8 ffff88003b75bc04 > ffff88003b75bbe0 ffffed00076eb772 ffff88003b75bb90 000000003cb77ce0 > Call Trace: > [< inline >] htab_elem_free kernel/bpf/hashtab.c:388 > [< inline >] delete_all_elements kernel/bpf/hashtab.c:690 > [<ffffffff81392bcb>] htab_map_free+0x30b/0x470 kernel/bpf/hashtab.c:711 > [<ffffffff8137e9dc>] bpf_map_free_deferred+0xac/0xd0 kernel/bpf/syscall.c:97 > [<ffffffff8114f937>] process_one_work+0x8a7/0x1300 kernel/workqueue.c:2096 > [<ffffffff8115047d>] worker_thread+0xed/0x14e0 kernel/workqueue.c:2230 > [<ffffffff811619dc>] kthread+0x1ec/0x260 kernel/kthread.c:209 > [<ffffffff82fa78c5>] ret_from_fork+0x25/0x30 arch/x86/entry/entry_64.S:433 > Code: 83 c4 18 48 89 da 4c 89 ee ff d0 49 8b 04 24 48 85 c0 75 e6 e9 > e9 fe ff ff 49 8b 04 24 f6 c4 40 75 0b 49 8b 44 24 20 a8 01 75 02 <0f> > 0b 48 89 df e8 56 35 00 00 49 8b 04 24 31 f6 f6 c4 40 74 05 > RIP [< inline >] PageCompound ./include/linux/page-flags.h:157 > RIP [<ffffffff814c9f00>] kfree+0x140/0x1a0 mm/slub.c:3866 > RSP <ffff88003cb77c50> > ---[ end trace 1dc58d6aeb2596aa ]--- > ================================================================== > BUG: KASAN: stack-out-of-bounds in complete+0x68/0x70 at addr ffff88003cb77ed8 > Read of size 4 by task kworker/1:2/1542 > page:ffffea0000f2ddc0 count:0 mapcount:0 mapping: (null) index:0x0 > flags: 0x100000000000000() > page dumped because: kasan: bad access detected > CPU: 1 PID: 1542 Comm: kworker/1:2 Tainted: G D 4.9.0-rc3+ #20 > Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011 > ffff88003cb77ce0 ffffffff81acf609 ffffed000796efdb ffffed000796efdb > 0000000000000004 0000000000000000 ffff88003cb77d60 ffffffff814cdbfb > ffff88003c8d97c8 dffffc0000000000 ffffffff811dd038 0000000000000097 > Call Trace: > [< inline >] __dump_stack lib/dump_stack.c:15 > [<ffffffff81acf609>] dump_stack+0x83/0xba lib/dump_stack.c:51 > [< inline >] kasan_report_error mm/kasan/report.c:204 > [<ffffffff814cdbfb>] kasan_report+0x4cb/0x500 mm/kasan/report.c:303 > [<ffffffff814cdc84>] __asan_report_load4_noabort+0x14/0x20 > mm/kasan/report.c:328 > [<ffffffff811dd038>] complete+0x68/0x70 kernel/sched/completion.c:34 > [< inline >] complete_vfork_done kernel/fork.c:1030 > [<ffffffff810fa8c2>] mm_release+0x222/0x3f0 kernel/fork.c:1114 > [< inline >] exit_mm kernel/exit.c:467 > [<ffffffff8110b501>] do_exit+0x3a1/0x2960 kernel/exit.c:815 > [<ffffffff82fa8b97>] rewind_stack_do_exit+0x17/0x20 > arch/x86/entry/entry_64.S:1526 > Memory state around the buggy address: > ffff88003cb77d80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 > ffff88003cb77e00: 00 00 00 00 00 00 00 00 f1 f1 f1 f1 00 f4 f4 f4 >>ffff88003cb77e80: f2 f2 f2 f2 00 f4 f4 f4 f2 f2 f2 f2 00 00 f4 f4 > ^ > ffff88003cb77f00: f3 f3 f3 f3 00 00 00 00 00 00 00 00 00 00 00 00 > ffff88003cb77f80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 > ================================================================== > BUG: unable to handle kernel > paging request at ffffffffffffffd8 > IP: [<ffffffff81163c5d>] kthread_data+0x4d/0x70 kernel/kthread.c:137 > PGD 360d067 [ 48.581115] PUD 360f067 > PMD 0 [ 48.581840] > Oops: 0000 [#2] SMP KASAN > Modules linked in: > CPU: 1 PID: 1542 Comm: kworker/1:2 Tainted: G B D 4.9.0-rc3+ #20 > Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011 > task: ffff88003b9c0040 task.stack: ffff88003cb70000 > RIP: 0010:[<ffffffff81163c5d>] [<ffffffff81163c5d>] kthread_data+0x4d/0x70 > RSP: 0018:ffff88003cb77c78 EFLAGS: 00010046 > RAX: dffffc0000000000 RBX: 0000000000000000 RCX: 0000000000000000 > RDX: 1ffffffffffffffb RSI: ffff88003b9c00c0 RDI: ffffffffffffffd8 > RBP: ffff88003cb77c80 R08: ffff88003ed20a48 R09: ffff88003ed20a40 > R10: 0000000000000000 R11: 0000000000000000 R12: ffff88003ed20980 > R13: ffff88003b9c0040 R14: ffff88003b9c0094 R15: 0000000000000040 > FS: 0000000000000000(0000) GS:ffff88003ed00000(0000) knlGS:0000000000000000 > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > CR2: 0000000000000028 CR3: 000000000360c000 CR4: 00000000000006e0 > Stack: > ffff88003b9c0040 ffff88003cb77ca0 ffffffff81155e77 0000000000020980 > ffff88003ed20980 ffff88003cb77db8 ffffffff82f9b1a2 0000000000000000 > ffff88003ddd2670 00ff88003ddd2640 ffff88003ed211f8 1ffff1000796ef9e > Call Trace: > [<ffffffff81155e77>] wq_worker_sleeping+0x17/0x210 kernel/workqueue.c:876 > [<ffffffff82f9b1a2>] __schedule+0xc62/0x1730 kernel/sched/core.c:3380 > [<ffffffff8118c781>] do_task_dead+0x81/0xa0 kernel/sched/core.c:3431 > [<ffffffff8110c7f8>] do_exit+0x1698/0x2960 kernel/exit.c:885 > [<ffffffff82fa8b97>] rewind_stack_do_exit+0x17/0x20 > arch/x86/entry/entry_64.S:1526 > Code: c1 ea 03 80 3c 02 00 75 29 48 8b 9b 30 05 00 00 48 b8 00 00 00 > 00 00 fc ff df 48 8d 7b d8 48 89 fa 48 c1 ea 03 80 3c 02 00 75 0e <48> > 8b 43 d8 5b 5d c3 e8 27 a0 36 00 eb d0 e8 20 a0 36 00 eb eb > RIP [<ffffffff81163c5d>] kthread_data+0x4d/0x70 kernel/kthread.c:137 > RSP <ffff88003cb77c78> > CR2: ffffffffffffffd8 > ---[ end trace 1dc58d6aeb2596ab ]--- > Fixing recursive fault but reboot is needed! > > > // autogenerated by syzkaller (http://github.com/google/syzkaller) > > #ifndef __NR_bpf > #define __NR_bpf 321 > #endif > > #include <fcntl.h> > #include <pthread.h> > #include <signal.h> > #include <stddef.h> > #include <stdint.h> > #include <stdio.h> > #include <stdlib.h> > #include <string.h> > #include <sys/ioctl.h> > #include <sys/stat.h> > #include <sys/syscall.h> > #include <sys/types.h> > #include <unistd.h> > > long r[14]; > void* thr(void* arg) > { > switch ((long)arg) { > case 0: > r[0] = > syscall(__NR_mmap, 0x20000000ul, 0x16000ul, 0x3ul, > 0x32ul, 0xfffffffffffffffful, 0x0ul, 0, 0, 0); > break; > case 1: > (*(uint32_t*)0x20011000 = (uint32_t)0x1); > (*(uint32_t*)0x20011004 = (uint32_t)0x8); > (*(uint32_t*)0x20011008 = (uint32_t)0x3); > (*(uint32_t*)0x2001100c = (uint32_t)0x1); > (*(uint32_t*)0x20011010 = (uint32_t)0x1); > r[6] = syscall(__NR_bpf, 0x0ul, 0x20011000ul, 0x14ul, 0, 0, > 0, 0, 0, 0); > break; > case 2: > (*(uint32_t*)0x20013000 = r[6]); > (*(uint64_t*)0x20013008 = (uint64_t)0x20013fb3); > (*(uint64_t*)0x20013010 = (uint64_t)0x20012ff1); > (*(uint64_t*)0x20013018 = (uint64_t)0x0); > (memcpy( > (void*)0x20013fb3, > "\x3e\x51\x32\xbe\xd5\x24\x20\xb2\x50\x7a\x4d\xb5\xec\xb3\x8f" > "\x65\x7f\xac\x61\x9a\xf0\x29\x3f\x77\x07\x2f\x2f\x60\xe9\x78" > "\xc5\x79\x45\x16\x67\xf6\x64\xb4\xd5\xb2\x11\x88\x5f\x4f\x32" > "\xba\xa8\x80\x8f\x7a\xea\x01\x1d\xe4\x08\xa4\x65\x73\x07\x91" > "\x48\xd5\xc3\xf2\xc4\x08\x29\x8f\x88\x95\xc3\xd5\xf6\x86\x0f" > "\x42\xab\x05\xf7\xfa\x2b\x12\x78\xb3\x4d\x17\x8c\x27\x57\x8b" > "\x79\xdc\x4f\x8a\x7a\xf5\x8c\x8a\xc2\x18\x03\xa0\xf9\x5f\x7a", > 105)); > (memcpy( > (void*)0x20012ff1, > "\xb1\xb0\x4b\x14\x9e\xfa\xbc\xb2\xaf\x4b\x4a\x02\xbc\x9b\xc5", > 15)); > r[13] = syscall(__NR_bpf, 0x2ul, 0x20013000ul, 0x20ul, 0, 0, > 0, 0, 0, 0); > break; > } > return 0; > } > > int main() > { > long i; > pthread_t th[6]; > > memset(r, -1, sizeof(r)); > srand(getpid()); > for (i = 0; i < 3; i++) { > pthread_create(&th[i], 0, thr, (void*)i); > usleep(10000); > } > for (i = 0; i < 3; i++) { > pthread_create(&th[3 + i], 0, thr, (void*)i); > if (rand() % 2) > usleep(rand() % 10000); > } > usleep(100000); > return 0; > }
Sometimes it crashes with "unable to handle kernel paging request" : BUG: unable to handle kernel paging request at ffffeb83fffec020 IP: [< inline >] virt_to_head_page include/linux/mm.h:555 IP: [<ffffffff814c9e15>] kfree+0x55/0x1a0 mm/slub.c:3864 PGD 0 [ 1103.309066] Oops: 0000 [#1] SMP KASAN Dumping ftrace buffer: (ftrace buffer empty) Modules linked in: CPU: 3 PID: 5460 Comm: kworker/3:3 Not tainted 4.9.0-rc3+ #20 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011 Workqueue: events bpf_map_free_deferred task: ffff8800676b6e40 task.stack: ffff880067680000 RIP: 0010:[<ffffffff814c9e15>] [< inline >] virt_to_head_page include/linux/mm.h:555 RIP: 0010:[<ffffffff814c9e15>] [<ffffffff814c9e15>] kfree+0x55/0x1a0 mm/slub.c:3864 RSP: 0018:ffff880067687c50 EFLAGS: 00010286 RAX: ffffea0000000000 RBX: ffffe8ffffb00748 RCX: 0000000000000000 RDX: 0000000000000000 RSI: 1ffff1000db56cb5 RDI: ffffe8ffffb00748 RBP: ffff880067687c70 R08: 0000000000003400 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: ffffeb83fffec000 R13: ffffffff81392bcb R14: 0000000000000000 R15: ffffe8ffffb00748 FS: 0000000000000000(0000) GS:ffff88006e500000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffffeb83fffec020 CR3: 000000003d24f000 CR4: 00000000000006e0 DR0: 0000000000000007 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600 Stack: dffffc0000000000 ffff88006dab65a8 ffff88006d0490c8 0000000000000000 ffff880067687ce0 ffffffff81392bcb ffffffff81acf4f8 ffff88006d049144 ffff88006d049120 ffffed000da0921a ffff88006d0490d0 0000000067687ce0 Call Trace: [< inline >] htab_elem_free kernel/bpf/hashtab.c:388 [< inline >] delete_all_elements kernel/bpf/hashtab.c:690 [<ffffffff81392bcb>] htab_map_free+0x30b/0x470 kernel/bpf/hashtab.c:711 [<ffffffff8137e9dc>] bpf_map_free_deferred+0xac/0xd0 kernel/bpf/syscall.c:97 [<ffffffff8114f937>] process_one_work+0x8a7/0x1300 kernel/workqueue.c:2096 [<ffffffff8115047d>] worker_thread+0xed/0x14e0 kernel/workqueue.c:2230 [<ffffffff811619dc>] kthread+0x1ec/0x260 kernel/kthread.c:209 [<ffffffff82fa78c5>] ret_from_fork+0x25/0x30 arch/x86/entry/entry_64.S:433 Code: 48 01 d8 0f 82 53 01 00 00 49 bc 00 00 00 80 ff 77 00 00 49 01 c4 48 b8 00 00 00 00 00 ea ff ff 49 c1 ec 0c 49 c1 e4 06 49 01 c4 <49> 8b 44 24 20 48 8d 50 ff a8 01 4c 0f 45 e2 49 8b 54 24 20 48 RIP [< inline >] virt_to_head_page include/linux/mm.h:555 RIP [<ffffffff814c9e15>] kfree+0x55/0x1a0 mm/slub.c:3864 RSP <ffff880067687c50> CR2: ffffeb83fffec020 ---[ end trace 9271605118c02ee3 ]--- Kernel panic - not syncing: Fatal exception Dumping ftrace buffer: (ftrace buffer empty) Kernel Offset: disabled reboot: cpu_has_vmx: ecx=80a02021 1