On Sun, 13 Oct 2024 at 13:01, syzbot <syzbot+8cb2efaaad483f65f56c@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote: > > Hello, > > syzbot found the following issue on: > > HEAD commit: 7234e2ea0edd Merge tag 'scsi-fixes' of git://git.kernel.or.. > git tree: upstream > console output: https://syzkaller.appspot.com/x/log.txt?x=157a085f980000 > kernel config: https://syzkaller.appspot.com/x/.config?x=7cd9e7e4a8a0a15b > dashboard link: https://syzkaller.appspot.com/bug?extid=8cb2efaaad483f65f56c > compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40 > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=146c7fd0580000 > > Downloadable assets: > disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/7feb34a89c2a/non_bootable_disk-7234e2ea.raw.xz > vmlinux: https://storage.googleapis.com/syzbot-assets/aa111520a0b7/vmlinux-7234e2ea.xz > kernel image: https://storage.googleapis.com/syzbot-assets/07889fadba3b/bzImage-7234e2ea.xz > mounted in repro #1: https://storage.googleapis.com/syzbot-assets/178fe4a5f5e7/mount_1.gz > mounted in repro #2: https://storage.googleapis.com/syzbot-assets/7847e1862894/mount_2.gz > > IMPORTANT: if you fix the issue, please add the following tag to the commit: > Reported-by: syzbot+8cb2efaaad483f65f56c@xxxxxxxxxxxxxxxxxxxxxxxxx > > loop0: detected capacity change from 0 to 256 > exFAT-fs (loop0): failed to load upcase table (idx : 0x00010000, chksum : 0xcc9b7de9, utbl_chksum : 0xe619d30d) > Oops: stack segment: 0000 [#1] PREEMPT SMP KASAN NOPTI > CPU: 0 UID: 0 PID: 5340 Comm: syz.0.50 Not tainted 6.12.0-rc2-syzkaller-00305-g7234e2ea0edd #0 > Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014 > RIP: 0010:PageTail include/linux/page-flags.h:281 [inline] > RIP: 0010:const_folio_flags include/linux/page-flags.h:309 [inline] > RIP: 0010:folio_test_writeback include/linux/page-flags.h:555 [inline] > RIP: 0010:folio_wait_writeback+0x2f/0x1e0 mm/page-writeback.c:3187 > Code: 41 57 41 56 41 55 41 54 53 48 83 ec 18 48 89 fb 49 bd 00 00 00 00 00 fc ff df e8 ac 7e c4 ff 4c 8d 73 08 4c 89 f5 48 c1 ed 03 <42> 80 7c 2d 00 00 74 08 4c 89 f7 e8 11 2f 2e 00 4d 8b 3e 4c 89 fe > RSP: 0018:ffffc900025a7190 EFLAGS: 00010202 > RAX: ffffffff81d068a4 RBX: 0000000000000000 RCX: ffff888000c3c880 > RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000 > RBP: 0000000000000001 R08: ffffffff81cc460e R09: 1ffffd4000003328 > R10: dffffc0000000000 R11: fffff94000003329 R12: dffffc0000000000 > R13: dffffc0000000000 R14: 0000000000000008 R15: 0000000000000001 > FS: 00007f7a897816c0(0000) GS:ffff88801fc00000(0000) knlGS:0000000000000000 > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > CR2: 00007f7a88a75c60 CR3: 000000003f406000 CR4: 0000000000352ef0 > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 > Call Trace: > <TASK> > __filemap_fdatawait_range+0x17c/0x2b0 mm/filemap.c:533 > file_write_and_wait_range+0x1e3/0x280 mm/filemap.c:792 > __generic_file_fsync+0x6f/0x1a0 fs/libfs.c:1528 > exfat_file_fsync+0xf9/0x1d0 fs/exfat/file.c:524 > exfat_file_write_iter+0x312/0x3f0 fs/exfat/file.c:608 > iter_file_splice_write+0xbfa/0x1510 fs/splice.c:743 > do_splice_from fs/splice.c:941 [inline] > direct_splice_actor+0x11b/0x220 fs/splice.c:1164 > splice_direct_to_actor+0x586/0xc80 fs/splice.c:1108 > do_splice_direct_actor fs/splice.c:1207 [inline] > do_splice_direct+0x289/0x3e0 fs/splice.c:1233 > do_sendfile+0x561/0xe10 fs/read_write.c:1388 > __do_sys_sendfile64 fs/read_write.c:1455 [inline] > __se_sys_sendfile64+0x17c/0x1e0 fs/read_write.c:1441 > do_syscall_x64 arch/x86/entry/common.c:52 [inline] > do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 > entry_SYSCALL_64_after_hwframe+0x77/0x7f > RIP: 0033:0x7f7a8897dff9 > Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48 > RSP: 002b:00007f7a89781038 EFLAGS: 00000246 ORIG_RAX: 0000000000000028 > RAX: ffffffffffffffda RBX: 00007f7a88b35f80 RCX: 00007f7a8897dff9 > RDX: 0000000000000000 RSI: 0000000000000005 RDI: 0000000000000004 > RBP: 00007f7a889f0296 R08: 0000000000000000 R09: 0000000000000000 > R10: 0000000000100001 R11: 0000000000000246 R12: 0000000000000000 > R13: 0000000000000000 R14: 00007f7a88b35f80 R15: 00007fffbdf78608 > </TASK> > Modules linked in: > ---[ end trace 0000000000000000 ]--- > RIP: 0010:PageTail include/linux/page-flags.h:281 [inline] > RIP: 0010:const_folio_flags include/linux/page-flags.h:309 [inline] > RIP: 0010:folio_test_writeback include/linux/page-flags.h:555 [inline] > RIP: 0010:folio_wait_writeback+0x2f/0x1e0 mm/page-writeback.c:3187 > Code: 41 57 41 56 41 55 41 54 53 48 83 ec 18 48 89 fb 49 bd 00 00 00 00 00 fc ff df e8 ac 7e c4 ff 4c 8d 73 08 4c 89 f5 48 c1 ed 03 <42> 80 7c 2d 00 00 74 08 4c 89 f7 e8 11 2f 2e 00 4d 8b 3e 4c 89 fe > RSP: 0018:ffffc900025a7190 EFLAGS: 00010202 > RAX: ffffffff81d068a4 RBX: 0000000000000000 RCX: ffff888000c3c880 > RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000 > RBP: 0000000000000001 R08: ffffffff81cc460e R09: 1ffffd4000003328 > R10: dffffc0000000000 R11: fffff94000003329 R12: dffffc0000000000 > R13: dffffc0000000000 R14: 0000000000000008 R15: 0000000000000001 > FS: 00007f7a897816c0(0000) GS:ffff88801fc00000(0000) knlGS:0000000000000000 > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > CR2: 00007f7a8975ff98 CR3: 000000003f406000 CR4: 0000000000352ef0 > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 > ---------------- > Code disassembly (best guess): > 0: 41 57 push %r15 > 2: 41 56 push %r14 > 4: 41 55 push %r13 > 6: 41 54 push %r12 > 8: 53 push %rbx > 9: 48 83 ec 18 sub $0x18,%rsp > d: 48 89 fb mov %rdi,%rbx > 10: 49 bd 00 00 00 00 00 movabs $0xdffffc0000000000,%r13 > 17: fc ff df > 1a: e8 ac 7e c4 ff call 0xffc47ecb > 1f: 4c 8d 73 08 lea 0x8(%rbx),%r14 > 23: 4c 89 f5 mov %r14,%rbp > 26: 48 c1 ed 03 shr $0x3,%rbp > * 2a: 42 80 7c 2d 00 00 cmpb $0x0,0x0(%rbp,%r13,1) <-- trapping instruction +tracing maintainers Not sure how this instruction can cause stack segment violation. The reproducer does something with raw tracepoints: https://syzkaller.appspot.com/text?tag=ReproSyz&x=146c7fd0580000 Can raw tracepoints legally arbitrary corrupt kernel state? If yes, is there some safe subset at least? > 30: 74 08 je 0x3a > 32: 4c 89 f7 mov %r14,%rdi > 35: e8 11 2f 2e 00 call 0x2e2f4b > 3a: 4d 8b 3e mov (%r14),%r15 > 3d: 4c 89 fe mov %r15,%rsi > > > --- > 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. > > If the report is already addressed, let syzbot know by replying with: > #syz fix: exact-commit-title > > If you want syzbot to run the reproducer, reply with: > #syz test: git://repo/address.git branch-or-commit-hash > If you attach or paste a git patch, syzbot will apply it before testing. > > If you want to overwrite report's subsystems, reply with: > #syz set subsystems: new-subsystem > (See the list of subsystem names on the web dashboard) > > If the report is a duplicate of another one, reply with: > #syz dup: exact-subject-of-another-report > > If you want to undo deduplication, reply with: > #syz undup
