On 2/28/19 10:53 AM, Dmitry Vyukov wrote: > On Thu, Feb 28, 2019 at 6:51 PM Jens Axboe <axboe@xxxxxxxxx> wrote: >> >> On 2/28/19 10:42 AM, Eric Biggers wrote: >>> On Thu, Feb 28, 2019 at 11:36:21AM +0100, 'Dmitry Vyukov' via syzkaller-bugs wrote: >>>> On Thu, Feb 28, 2019 at 11:32 AM syzbot >>>> <syzbot+6f5a9b79b75b66078bf0@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote: >>>>> >>>>> Hello, >>>>> >>>>> syzbot found the following crash on: >>>>> >>>>> HEAD commit: 42fd8df9d1d9 Add linux-next specific files for 20190228 >>>>> git tree: linux-next >>>>> console output: https://syzkaller.appspot.com/x/log.txt?x=179ba9e0c00000 >>>>> kernel config: https://syzkaller.appspot.com/x/.config?x=c0f38652d28b522f >>>>> dashboard link: https://syzkaller.appspot.com/bug?extid=6f5a9b79b75b66078bf0 >>>>> compiler: gcc (GCC) 9.0.0 20181231 (experimental) >>>>> syz repro: https://syzkaller.appspot.com/x/repro.syz?x=12ed6bd0c00000 >>>>> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=10690c8ac00000 >>>>> >>>>> IMPORTANT: if you fix the bug, please add the following tag to the commit: >>>>> Reported-by: syzbot+6f5a9b79b75b66078bf0@xxxxxxxxxxxxxxxxxxxxxxxxx >>>> >>>> +Jens, Eric, >>>> >>>> Looks similar to: >>>> https://groups.google.com/forum/#!msg/syzkaller-bugs/E3v3XQweVBw/6BPrkIYJIgAJ >>>> Perhaps the fixing commit is not in the build yet? >>>> >>>> >>>>> BUG: Bad page state in process syz-executor193 pfn:9225a >>>>> page:ffffea0002489680 count:0 mapcount:0 mapping:ffff88808652fd80 index:0x81 >>>>> shmem_aops >>>>> name:"memfd:cgroup2" >>>>> flags: 0x1fffc000008000e(referenced|uptodate|dirty|swapbacked) >>>>> raw: 01fffc000008000e ffff88809277fac0 ffff88809277fac0 ffff88808652fd80 >>>>> raw: 0000000000000081 0000000000000000 00000000ffffffff 0000000000000000 >>>>> page dumped because: non-NULL mapping >>>>> Modules linked in: >>>>> CPU: 0 PID: 7659 Comm: syz-executor193 Not tainted 5.0.0-rc8-next-20190228 >>>>> #45 >>>>> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS >>>>> Google 01/01/2011 >>>>> Call Trace: >>>>> __dump_stack lib/dump_stack.c:77 [inline] >>>>> dump_stack+0x172/0x1f0 lib/dump_stack.c:113 >>>>> bad_page.cold+0xda/0xff mm/page_alloc.c:586 >>>>> free_pages_check_bad+0x142/0x1a0 mm/page_alloc.c:1013 >>>>> free_pages_check mm/page_alloc.c:1022 [inline] >>>>> free_pages_prepare mm/page_alloc.c:1112 [inline] >>>>> free_pcp_prepare mm/page_alloc.c:1137 [inline] >>>>> free_unref_page_prepare mm/page_alloc.c:3001 [inline] >>>>> free_unref_page_list+0x31d/0xc40 mm/page_alloc.c:3070 >>>>> release_pages+0x60d/0x1940 mm/swap.c:794 >>>>> pagevec_lru_move_fn+0x218/0x2a0 mm/swap.c:213 >>>>> activate_page_drain mm/swap.c:297 [inline] >>>>> lru_add_drain_cpu+0x3b1/0x520 mm/swap.c:596 >>>>> lru_add_drain+0x20/0x60 mm/swap.c:647 >>>>> exit_mmap+0x290/0x530 mm/mmap.c:3134 >>>>> __mmput kernel/fork.c:1047 [inline] >>>>> mmput+0x15f/0x4c0 kernel/fork.c:1068 >>>>> exit_mm kernel/exit.c:546 [inline] >>>>> do_exit+0x816/0x2fa0 kernel/exit.c:863 >>>>> do_group_exit+0x135/0x370 kernel/exit.c:980 >>>>> __do_sys_exit_group kernel/exit.c:991 [inline] >>>>> __se_sys_exit_group kernel/exit.c:989 [inline] >>>>> __x64_sys_exit_group+0x44/0x50 kernel/exit.c:989 >>>>> do_syscall_64+0x103/0x610 arch/x86/entry/common.c:290 >>>>> entry_SYSCALL_64_after_hwframe+0x49/0xbe >>>>> RIP: 0033:0x442a58 >>>>> Code: 00 00 be 3c 00 00 00 eb 19 66 0f 1f 84 00 00 00 00 00 48 89 d7 89 f0 >>>>> 0f 05 48 3d 00 f0 ff ff 77 21 f4 48 89 d7 44 89 c0 0f 05 <48> 3d 00 f0 ff >>>>> ff 76 e0 f7 d8 64 41 89 01 eb d8 0f 1f 84 00 00 00 >>>>> RSP: 002b:00007ffe99e2faf8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 >>>>> RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000442a58 >>>>> RDX: 0000000000000000 RSI: 000000000000003c RDI: 0000000000000000 >>>>> RBP: 00000000004c2468 R08: 00000000000000e7 R09: ffffffffffffffd0 >>>>> R10: 0000000002000005 R11: 0000000000000246 R12: 0000000000000001 >>>>> R13: 00000000006d4180 R14: 0000000000000000 R15: 0000000000000000 >>>>> >>>>> >>>>> --- >>>>> 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 syzkaller@xxxxxxxxxxxxxxxx. >>>>> >>>>> syzbot will keep track of this bug report. See: >>>>> https://goo.gl/tpsmEJ#bug-status-tracking 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 syzkaller-bugs+unsubscribe@xxxxxxxxxxxxxxxx. >>>>> To view this discussion on the web visit https://groups.google.com/d/msgid/syzkaller-bugs/00000000000024b3aa0582f1cde7%40google.com. >>>>> For more options, visit https://groups.google.com/d/optout. >>>> >>>> -- >>>> 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/CACT4Y%2BbyrcaasUaEJj%3DhcemEEBBkon%3DVC24gPwGXHzfeRP0E3w%40mail.gmail.com. >>>> For more options, visit https://groups.google.com/d/optout. >>> >>> It bisects down to the same patch ("block: implement bio helper to add iter bvec >>> pages to bio") so apparently it's just still broken despite Jens' fix. >>> >>> BTW, as this is trivially bisectable with the reproducer, I still don't see why >>> syzbot can't do the bisection itself and use get_maintainer.pl on the broken >>> patch to actually send the report to the right person: >>> >>> $ ./scripts/get_maintainer.pl 0001-block-implement-bio-helper-to-add-iter-bvec-pages-to.patch >>> Jens Axboe <axboe@xxxxxxxxx> (maintainer:BLOCK LAYER) >>> linux-block@xxxxxxxxxxxxxxx (open list:BLOCK LAYER) >>> linux-kernel@xxxxxxxxxxxxxxx (open list) >>> >>> Spamming unrelated lists and maintainers not only prevents the bug from being >>> fixed, but it also reduces the average usefulness of syzbot reports which >>> teaches people to ignore them. >> >> Huh, weird. Where's the reproducer for this one? > > Under the "C reproducer" link. Got it, for some reason I overlooked that. Thanks. -- Jens Axboe
