Re: [syzbot] [fs?] general protection fault in pagemap_scan_hugetlb_entry

[syzbot]

> #syz test https://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git/log/?h=mm-hotfixes-unstable
>
> ________________________________
> From: syzbot <syzbot+6e2ccedb96d1174e6a5f@xxxxxxxxxxxxxxxxxxxxxxxxx>
> Sent: Saturday, December 2, 2023 6:17 PM
> To: akpm@xxxxxxxxxxxxxxxxxxxx <akpm@xxxxxxxxxxxxxxxxxxxx>; dan.carpenter@xxxxxxxxxx <dan.carpenter@xxxxxxxxxx>; linux-fsdevel@xxxxxxxxxxxxxxx <linux-fsdevel@xxxxxxxxxxxxxxx>; linux-kernel@xxxxxxxxxxxxxxx <linux-kernel@xxxxxxxxxxxxxxx>; linux-mm@xxxxxxxxx <linux-mm@xxxxxxxxx>; llvm@xxxxxxxxxxxxxxx <llvm@xxxxxxxxxxxxxxx>; Mike Kravetz <mike.kravetz@xxxxxxxxxx>; muchun.song@xxxxxxxxx <muchun.song@xxxxxxxxx>; nathan@xxxxxxxxxx <nathan@xxxxxxxxxx>; ndesaulniers@xxxxxxxxxx <ndesaulniers@xxxxxxxxxx>; Sidhartha Kumar <sidhartha.kumar@xxxxxxxxxx>; syzkaller-bugs@xxxxxxxxxxxxxxxx <syzkaller-bugs@xxxxxxxxxxxxxxxx>; trix@xxxxxxxxxx <trix@xxxxxxxxxx>
> Subject: [syzbot] [fs?] general protection fault in pagemap_scan_hugetlb_entry
>
> Hello,
>
> syzbot found the following issue on:
>
> HEAD commit:    df60cee26a2e Merge tag '6.7-rc3-smb3-server-fixes' of git:..
> git tree:       upstream
> console+strace: https://syzkaller.appspot.com/x/log.txt?x=17ad46fce80000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=bb39fe85d254f638
> dashboard link: https://syzkaller.appspot.com/bug?extid=6e2ccedb96d1174e6a5f
> compiler:       gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
> syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=17befd62e80000
> C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=10d5a90ce80000
>
> Downloadable assets:
> disk image: https://storage.googleapis.com/syzbot-assets/c632017e0dc4/disk-df60cee2.raw.xz
> vmlinux: https://storage.googleapis.com/syzbot-assets/f94c8fa25aeb/vmlinux-df60cee2.xz
> kernel image: https://storage.googleapis.com/syzbot-assets/af80f80c708b/bzImage-df60cee2.xz
>
> The issue was bisected to:
>
> commit a08c7193e4f18dc8508f2d07d0de2c5b94cb39a3
> Author: Sidhartha Kumar <sidhartha.kumar@xxxxxxxxxx>
> Date:   Tue Sep 26 19:20:17 2023 +0000
>
>     mm/filemap: remove hugetlb special casing in filemap.c
>
> bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=17f61552e80000
> final oops:     https://syzkaller.appspot.com/x/report.txt?x=140e1552e80000
> console output: https://syzkaller.appspot.com/x/log.txt?x=100e1552e80000
>
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: syzbot+6e2ccedb96d1174e6a5f@xxxxxxxxxxxxxxxxxxxxxxxxx
> Fixes: a08c7193e4f1 ("mm/filemap: remove hugetlb special casing in filemap.c")
>
> general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] PREEMPT SMP KASAN
> KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
> CPU: 0 PID: 5072 Comm: syz-executor107 Not tainted 6.7.0-rc3-syzkaller-00014-gdf60cee26a2e #0
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/10/2023
> RIP: 0010:pagemap_scan_backout_range fs/proc/task_mmu.c:1946 [inline]
> RIP: 0010:pagemap_scan_hugetlb_entry+0x6ca/0x1130 fs/proc/task_mmu.c:2254
> Code: 3c 02 00 0f 85 68 09 00 00 48 8b 83 80 00 00 00 48 8d 04 40 4d 8d 6c c5 00 48 b8 00 00 00 00 00 fc ff df 4c 89 ea 48 c1 ea 03 <80> 3c 02 00 0f 85 51 09 00 00 4d 8b 75 00 48 8b 7c 24 08 4c 89 f6
> RSP: 0018:ffffc90003a2fa50 EFLAGS: 00010246
> RAX: dffffc0000000000 RBX: ffffc90003a2fdb0 RCX: ffffffff82111e46
> RDX: 0000000000000000 RSI: ffffffff82111e54 RDI: ffffc90003a2fe30
> RBP: 1ffff92000745f52 R08: 0000000000000006 R09: 0000000020ffc000
> R10: 00000000211f9000 R11: ffffffff915f5de8 R12: ffff8880299e0300
> R13: 0000000000000000 R14: 0000000000000000 R15: 0000000020ffc000
> FS:  0000555555c7b380(0000) GS:ffff8880b9800000(0000) knlGS:0000000000000000
> CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 00000000005fdeb8 CR3: 00000000752b4000 CR4: 00000000003506f0
> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
> Call Trace:
>  <TASK>
>  walk_hugetlb_range mm/pagewalk.c:326 [inline]
>  __walk_page_range+0x36c/0x770 mm/pagewalk.c:393
>  walk_page_range+0x626/0xa80 mm/pagewalk.c:521
>  do_pagemap_scan+0x40d/0xcd0 fs/proc/task_mmu.c:2437
>  do_pagemap_cmd+0x5e/0x80 fs/proc/task_mmu.c:2478
>  vfs_ioctl fs/ioctl.c:51 [inline]
>  __do_sys_ioctl fs/ioctl.c:871 [inline]
>  __se_sys_ioctl fs/ioctl.c:857 [inline]
>  __x64_sys_ioctl+0x18f/0x210 fs/ioctl.c:857
>  do_syscall_x64 arch/x86/entry/common.c:51 [inline]
>  do_syscall_64+0x40/0x110 arch/x86/entry/common.c:82
>  entry_SYSCALL_64_after_hwframe+0x63/0x6b
> RIP: 0033:0x7f171819d669
> Code: 48 83 c4 28 c3 e8 37 17 00 00 0f 1f 80 00 00 00 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 b8 ff ff ff f7 d8 64 89 01 48
> RSP: 002b:00007fffbe81bb68 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
> RAX: ffffffffffffffda RBX: 00007fffbe81bb80 RCX: 00007f171819d669
> RDX: 0000000020000040 RSI: 00000000c0606610 RDI: 0000000000000003
> RBP: 00007f1718210610 R08: 0000000000000000 R09: 0000000000000000
> R10: 0000000000000286 R11: 0000000000000246 R12: 0000000000000001
> R13: 00007fffbe81bdb8 R14: 0000000000000001 R15: 0000000000000001
>  </TASK>
> Modules linked in:
> ---[ end trace 0000000000000000 ]---
> RIP: 0010:pagemap_scan_backout_range fs/proc/task_mmu.c:1946 [inline]
> RIP: 0010:pagemap_scan_hugetlb_entry+0x6ca/0x1130 fs/proc/task_mmu.c:2254
> Code: 3c 02 00 0f 85 68 09 00 00 48 8b 83 80 00 00 00 48 8d 04 40 4d 8d 6c c5 00 48 b8 00 00 00 00 00 fc ff df 4c 89 ea 48 c1 ea 03 <80> 3c 02 00 0f 85 51 09 00 00 4d 8b 75 00 48 8b 7c 24 08 4c 89 f6
> RSP: 0018:ffffc90003a2fa50 EFLAGS: 00010246
> RAX: dffffc0000000000 RBX: ffffc90003a2fdb0 RCX: ffffffff82111e46
> RDX: 0000000000000000 RSI: ffffffff82111e54 RDI: ffffc90003a2fe30
> RBP: 1ffff92000745f52 R08: 0000000000000006 R09: 0000000020ffc000
> R10: 00000000211f9000 R11: ffffffff915f5de8 R12: ffff8880299e0300
> R13: 0000000000000000 R14: 0000000000000000 R15: 0000000020ffc000
> FS:  0000555555c7b380(0000) GS:ffff8880b9800000(0000) knlGS:0000000000000000
> CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 00000000005fdeb8 CR3: 00000000752b4000 CR4: 00000000003506f0
> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
> ----------------
> Code disassembly (best guess):
>    0:   3c 02                    cmp    $0x2,%al
>    2:   00 0f                    add    %cl,(%rdi)
>    4:   85 68 09                 test   %ebp,0x9(%rax)
>    7:   00 00                    add    %al,(%rax)
>    9:   48 8b 83 80 00 00 00     mov    0x80(%rbx),%rax
>   10:   48 8d 04 40              lea    (%rax,%rax,2),%rax
>   14:   4d 8d 6c c5 00           lea    0x0(%r13,%rax,8),%r13
>   19:   48 b8 00 00 00 00 00     movabs $0xdffffc0000000000,%rax
>   20:   fc ff df
>   23:   4c 89 ea                 mov    %r13,%rdx
>   26:   48 c1 ea 03              shr    $0x3,%rdx
> * 2a:   80 3c 02 00              cmpb   $0x0,(%rdx,%rax,1) <-- trapping instruction
>   2e:   0f 85 51 09 00 00        jne    0x985
>   34:   4d 8b 75 00              mov    0x0(%r13),%r14
>   38:   48 8b 7c 24 08           mov    0x8(%rsp),%rdi
>   3d:   4c 89 f6                 mov    %r14,%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.
>
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> For information about bisection process see: https://goo.gl/tpsmEJ#bisection
>
> If the report is already addressed, let syzbot know by replying with:
> #syz fix: exact-commit-title
>
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> #syz test: git://repo/address.git branch-or-commit-hash
> If you attach or paste a git patch, syzbot will apply it before testing.
>
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>
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>
> If you want to undo deduplication, reply with:
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Command #1:
want either no args or 2 args (repo, branch), got 1