On Sat, Jul 4, 2020 at 8:34 PM Dmitry Vyukov <[email protected]> wrote: > > On Sat, Jul 4, 2020 at 6:45 PM Paul E. McKenney <[email protected]> wrote: > > > > On Fri, Jul 03, 2020 at 04:31:22PM -0700, syzbot wrote: > > > Hello, > > > > > > syzbot found the following crash on: > > > > > > HEAD commit: 9e50b94b Add linux-next specific files for 20200703 > > > git tree: linux-next > > > console output: https://syzkaller.appspot.com/x/log.txt?x=1024b405100000 > > > kernel config: https://syzkaller.appspot.com/x/.config?x=f99cc0faa1476ed6 > > > dashboard link: > > > https://syzkaller.appspot.com/bug?extid=0f719294463916a3fc0e > > > compiler: gcc (GCC) 10.1.0-syz 20200507 > > > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=16dc490f100000 > > > > > > IMPORTANT: if you fix the bug, please add the following tag to the commit: > > > Reported-by: [email protected] > > > > Good catch! A call to csd_lock_record() was on the wrong side of a > > call to csd_unlock(). > > Thanks for taking a look. > > > But is folded into another commit for bisectability reasons, so > > "Reported-by" would not make sense. I have instead added this to the > > commit log: > > > > [ paulmck: Fix for [email protected] ] > > Link: https://lore.kernel.org/lkml/[email protected] > > Link: https://lore.kernel.org/lkml/[email protected] > > This should work, as far as I remember sybot looks for the email+hash > anywhere in the commit. > FWIW Tested-by can make sense as well.
Paul, there is also some spike of stalls in smp_call_function, if you look at the top ones at: https://syzkaller.appspot.com/upstream#open Can these be caused by the same root cause? I am not sure what trees the bug was/is present... This seems to only happen on linux-next and nowhere else. But these stalls equally happen on mainline... > > Thanx, Paul > > > > > ================================================================== > > > BUG: KASAN: stack-out-of-bounds in csd_lock_record+0xcb/0xe0 > > > kernel/smp.c:118 > > > Read of size 8 at addr ffffc90001727710 by task syz-executor.0/10721 > > > > > > CPU: 1 PID: 10721 Comm: syz-executor.0 Not tainted > > > 5.8.0-rc3-next-20200703-syzkaller #0 > > > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS > > > Google 01/01/2011 > > > Call Trace: > > > <IRQ> > > > __dump_stack lib/dump_stack.c:77 [inline] > > > dump_stack+0x18f/0x20d lib/dump_stack.c:118 > > > print_address_description.constprop.0.cold+0x5/0x436 > > > mm/kasan/report.c:383 > > > __kasan_report mm/kasan/report.c:513 [inline] > > > kasan_report.cold+0x1f/0x37 mm/kasan/report.c:530 > > > csd_lock_record+0xcb/0xe0 kernel/smp.c:118 > > > flush_smp_call_function_queue+0x285/0x730 kernel/smp.c:391 > > > __sysvec_call_function_single+0x98/0x490 arch/x86/kernel/smp.c:248 > > > asm_call_on_stack+0xf/0x20 arch/x86/entry/entry_64.S:706 > > > </IRQ> > > > __run_on_irqstack arch/x86/include/asm/irq_stack.h:22 [inline] > > > run_on_irqstack_cond arch/x86/include/asm/irq_stack.h:48 [inline] > > > sysvec_call_function_single+0xe0/0x120 arch/x86/kernel/smp.c:243 > > > asm_sysvec_call_function_single+0x12/0x20 > > > arch/x86/include/asm/idtentry.h:604 > > > RIP: 0010:arch_local_irq_restore arch/x86/include/asm/paravirt.h:765 > > > [inline] > > > RIP: 0010:__raw_spin_unlock_irqrestore > > > include/linux/spinlock_api_smp.h:160 [inline] > > > RIP: 0010:_raw_spin_unlock_irqrestore+0x8c/0xe0 > > > kernel/locking/spinlock.c:191 > > > Code: 48 c7 c0 00 ff b4 89 48 ba 00 00 00 00 00 fc ff df 48 c1 e8 03 80 > > > 3c 10 00 75 37 48 83 3d 9b 74 c8 01 00 74 22 48 89 df 57 9d <0f> 1f 44 00 > > > 00 bf 01 00 00 00 e8 95 fb 62 f9 65 8b 05 fe 73 15 78 > > > RSP: 0018:ffffc900016e7558 EFLAGS: 00000282 > > > RAX: 1ffffffff1369fe0 RBX: 0000000000000282 RCX: 0000000000000000 > > > RDX: dffffc0000000000 RSI: 0000000000000000 RDI: 0000000000000282 > > > RBP: ffffffff8cb02508 R08: 0000000000000000 R09: 0000000000000000 > > > R10: 0000000000000001 R11: 0000000000000000 R12: 1ffffffff19604a0 > > > R13: 0000000000000000 R14: dead000000000100 R15: dffffc0000000000 > > > __debug_check_no_obj_freed lib/debugobjects.c:977 [inline] > > > debug_check_no_obj_freed+0x20c/0x41c lib/debugobjects.c:998 > > > free_pages_prepare mm/page_alloc.c:1219 [inline] > > > __free_pages_ok+0x20b/0xc90 mm/page_alloc.c:1471 > > > release_pages+0x5ec/0x17a0 mm/swap.c:880 > > > tlb_batch_pages_flush mm/mmu_gather.c:49 [inline] > > > tlb_flush_mmu_free mm/mmu_gather.c:242 [inline] > > > tlb_flush_mmu+0xe9/0x6b0 mm/mmu_gather.c:249 > > > zap_pte_range mm/memory.c:1155 [inline] > > > zap_pmd_range mm/memory.c:1193 [inline] > > > zap_pud_range mm/memory.c:1222 [inline] > > > zap_p4d_range mm/memory.c:1243 [inline] > > > unmap_page_range+0x1e22/0x2b20 mm/memory.c:1264 > > > unmap_single_vma+0x198/0x300 mm/memory.c:1309 > > > unmap_vmas+0x16f/0x2f0 mm/memory.c:1341 > > > exit_mmap+0x2b1/0x530 mm/mmap.c:3165 > > > __mmput+0x122/0x470 kernel/fork.c:1075 > > > mmput+0x53/0x60 kernel/fork.c:1096 > > > exit_mm kernel/exit.c:483 [inline] > > > do_exit+0xa8f/0x2a40 kernel/exit.c:793 > > > do_group_exit+0x125/0x310 kernel/exit.c:904 > > > get_signal+0x40b/0x1ee0 kernel/signal.c:2743 > > > do_signal+0x82/0x2520 arch/x86/kernel/signal.c:810 > > > exit_to_usermode_loop arch/x86/entry/common.c:218 [inline] > > > __prepare_exit_to_usermode+0x156/0x1f0 arch/x86/entry/common.c:252 > > > do_syscall_64+0x6c/0xe0 arch/x86/entry/common.c:376 > > > entry_SYSCALL_64_after_hwframe+0x44/0xa9 > > > RIP: 0033:0x45cb29 > > > Code: Bad RIP value. > > > RSP: 002b:00007fb154b96cf8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca > > > RAX: 0000000000000001 RBX: 000000000078bf08 RCX: 000000000045cb29 > > > RDX: 00000000000f4240 RSI: 0000000000000081 RDI: 000000000078bf0c > > > RBP: 000000000078bf00 R08: 0000000000000000 R09: 0000000000000000 > > > R10: 0000000000000000 R11: 0000000000000246 R12: 000000000078bf0c > > > R13: 00007ffd3933f26f R14: 00007fb154b979c0 R15: 000000000078bf0c > > > > > > > > > Memory state around the buggy address: > > > ffffc90001727600: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 > > > ffffc90001727680: 00 00 00 00 00 00 00 00 f1 f1 f1 f1 00 00 00 00 > > > >ffffc90001727700: f3 f3 f3 f3 00 00 00 00 00 00 00 00 00 00 00 00 > > > ^ > > > ffffc90001727780: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 > > > ffffc90001727800: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 > > > ================================================================== > > > > > > > > > --- > > > This bug 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 [email protected]. > > > > > > syzbot will keep track of this bug report. See: > > > https://goo.gl/tpsmEJ#status for how to communicate with syzbot. > > > syzbot can test patches for this bug, for details see: > > > https://goo.gl/tpsmEJ#testing-patches > > > > -- > > 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 [email protected]. > > To view this discussion on the web visit > > https://groups.google.com/d/msgid/syzkaller-bugs/20200704164522.GO9247%40paulmck-ThinkPad-P72.
