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? -- Jens Axboe
