On Sat, 21 Nov 2020 05:05:19 -0800 syzbot <syzbot+dcb847a3e1e0ecd191ab@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote: > Hello, > > syzbot found the following issue on: > > HEAD commit: 7c8ca812 Add linux-next specific files for 20201117 > git tree: linux-next > console output: https://syzkaller.appspot.com/x/log.txt?x=16ea946a500000 > kernel config: https://syzkaller.appspot.com/x/.config?x=ff4bc71371dc5b13 > dashboard link: https://syzkaller.appspot.com/bug?extid=dcb847a3e1e0ecd191ab > compiler: gcc (GCC) 10.1.0-syz 20200507 > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=14530c7a500000 > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=137c581c500000 > > IMPORTANT: if you fix the issue, please add the following tag to the commit: > Reported-by: syzbot+dcb847a3e1e0ecd191ab@xxxxxxxxxxxxxxxxxxxxxxxxx > > ------------[ cut here ]------------ > kernel BUG at include/linux/highmem.h:202! Thomas has changed the highmem code (well, kmap) quite a bit. But I don't think that's the culprit here. > invalid opcode: 0000 [#1] PREEMPT SMP KASAN > CPU: 0 PID: 8526 Comm: syz-executor603 Not tainted 5.10.0-rc4-next-20201117-syzkaller #0 > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 > RIP: 0010:zero_user_segments include/linux/highmem.h:202 [inline] > RIP: 0010:zero_user include/linux/highmem.h:223 [inline] > RIP: 0010:truncate_inode_partial_page+0x5aa/0x720 mm/truncate.c:264 > Code: bc 01 00 00 00 e8 e6 f8 ff ff e9 e7 fe ff ff e8 2c 12 d8 ff 48 c7 c6 00 44 54 89 48 89 ef e8 dd b5 08 00 0f 0b e8 16 12 d8 ff <0f> 0b e8 0f 12 d8 ff 48 c7 c6 80 44 54 89 48 89 ef e8 c0 b5 08 00 > RSP: 0018:ffffc90000f8fa00 EFLAGS: 00010293 > RAX: 0000000000000000 RBX: 0000000000200000 RCX: ffffffff81987fe1 > RDX: ffff88801e614f80 RSI: ffffffff819882ca RDI: 0000000000000005 > RBP: ffffea0000c70000 R08: 0000000000000000 R09: ffffea0000c70007 > R10: 0000000000001000 R11: 0000000000000000 R12: 00000000001ffffa > R13: 00000000001ffffa R14: 0000000000000006 R15: ffffea0000c70008 > FS: 0000000000e30880(0000) GS:ffff8880b9e00000(0000) knlGS:0000000000000000 > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > CR2: 000000000043e920 CR3: 00000000228a7000 CR4: 00000000001506f0 > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 > Call Trace: > shmem_undo_range+0x6fd/0x18f0 mm/shmem.c:921 > shmem_truncate_range mm/shmem.c:999 [inline] > shmem_setattr+0x67a/0xc70 mm/shmem.c:1058 > notify_change+0xb60/0x10a0 fs/attr.c:336 > do_truncate+0x134/0x1f0 fs/open.c:64 > vfs_truncate+0x49e/0x600 fs/open.c:110 > do_sys_truncate.part.0+0x11e/0x140 fs/open.c:133 > do_sys_truncate fs/open.c:127 [inline] > __do_sys_truncate fs/open.c:145 [inline] > __se_sys_truncate fs/open.c:143 [inline] > __x64_sys_truncate+0x69/0x90 fs/open.c:143 > do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 > entry_SYSCALL_64_after_hwframe+0x44/0xa9 Matthew's series "Overhaul multi-page lookups for THP" chnages the shmem code quite a bit, and in the area of truncate. Matthew, could you please fire up that reproducer? > RIP: 0033:0x444109 > Code: 18 89 d0 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 db d7 fb ff c3 66 2e 0f 1f 84 00 00 00 00 > RSP: 002b:00007ffec4a90088 EFLAGS: 00000246 ORIG_RAX: 000000000000004c > RAX: ffffffffffffffda RBX: 00000000004002e0 RCX: 0000000000444109 > RDX: 0000000000444109 RSI: 0000000000000006 RDI: 0000000020000040 > RBP: 00000000006ce018 R08: 0000000000000000 R09: 0000000000000000 > R10: 0000000000000005 R11: 0000000000000246 R12: 0000000000401d70 > R13: 0000000000401e00 R14: 0000000000000000 R15: 0000000000000000 > Modules linked in: > ---[ end trace 910e59f95b39ab18 ]--- > RIP: 0010:zero_user_segments include/linux/highmem.h:202 [inline] > RIP: 0010:zero_user include/linux/highmem.h:223 [inline] > RIP: 0010:truncate_inode_partial_page+0x5aa/0x720 mm/truncate.c:264 > Code: bc 01 00 00 00 e8 e6 f8 ff ff e9 e7 fe ff ff e8 2c 12 d8 ff 48 c7 c6 00 44 54 89 48 89 ef e8 dd b5 08 00 0f 0b e8 16 12 d8 ff <0f> 0b e8 0f 12 d8 ff 48 c7 c6 80 44 54 89 48 89 ef e8 c0 b5 08 00 > RSP: 0018:ffffc90000f8fa00 EFLAGS: 00010293 > RAX: 0000000000000000 RBX: 0000000000200000 RCX: ffffffff81987fe1 > RDX: ffff88801e614f80 RSI: ffffffff819882ca RDI: 0000000000000005 > RBP: ffffea0000c70000 R08: 0000000000000000 R09: ffffea0000c70007 > R10: 0000000000001000 R11: 0000000000000000 R12: 00000000001ffffa > R13: 00000000001ffffa R14: 0000000000000006 R15: ffffea0000c70008 > FS: 0000000000e30880(0000) GS:ffff8880b9e00000(0000) knlGS:0000000000000000 > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > CR2: 000000000043e920 CR3: 00000000228a7000 CR4: 00000000001506f0 > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 > > > --- > This report 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 issue. See: > https://goo.gl/tpsmEJ#status for how to communicate with syzbot. > syzbot can test patches for this issue, for details see: > https://goo.gl/tpsmEJ#testing-patches
