Re: [syzbot] [mm?] general protection fault in sys_mremap

From: Lorenzo Stoakes
Date: Wed Apr 02 2025 - 06:22:47 EST

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On Wed, Apr 02, 2025 at 03:20:04AM -0700, syzbot wrote:
> > Hi,
> >
> > This is already addressed in
> > https://lore.kernel.org/linux-mm/b2fb6b9c-376d-4e9b-905e-26d847fd3865@lucifer.local/
> > this just doesn't exist in -next/upstream yet.
> >
> > I _think_ we may be doing a 2nd PR for mm? But if not it'll be fixed in an
> > early rc.
> >
> > To make the point, friendly bot - let's have you try out the fix:
> >
> > #syz test: git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git/ mm-stable
>
> "git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git/" does not look like a valid git repo address.

#syz test: https://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git/ mm-stable
>
> >
> > Thanks, Lorenzo
> >
> > On Wed, Apr 02, 2025 at 03:01:20AM -0700, syzbot wrote:
> >> syzbot has found a reproducer for the following issue on:
> >>
> >> HEAD commit: acc4d5ff0b61 Merge tag 'net-6.15-rc0' of git://git.kernel...
> >> git tree: upstream
> >> console+strace: https://syzkaller.appspot.com/x/log.txt?x=16719404580000
> >> kernel config: https://syzkaller.appspot.com/x/.config?x=24f9c4330e7c0609
> >> dashboard link: https://syzkaller.appspot.com/bug?extid=e3385f43b2897a19be24
> >> 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=175a4fb0580000
> >> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1687b7b0580000
> >>
> >> Downloadable assets:
> >> disk image: https://storage.googleapis.com/syzbot-assets/e4bfa652b34a/disk-acc4d5ff.raw.xz
> >> vmlinux: https://storage.googleapis.com/syzbot-assets/3d19beb8bb92/vmlinux-acc4d5ff.xz
> >> kernel image: https://storage.googleapis.com/syzbot-assets/e7298ccc6331/bzImage-acc4d5ff.xz
> >>
> >> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> >> Reported-by: syzbot+e3385f43b2897a19be24@xxxxxxxxxxxxxxxxxxxxxxxxx
> >>
> >> Oops: general protection fault, probably for non-canonical address 0xdffffc0000000004: 0000 [#1] SMP KASAN PTI
> >> KASAN: null-ptr-deref in range [0x0000000000000020-0x0000000000000027]
> >> CPU: 0 UID: 0 PID: 5840 Comm: syz-executor163 Not tainted 6.14.0-syzkaller-12456-gacc4d5ff0b61 #0 PREEMPT(full)
> >> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
> >> RIP: 0010:vrm_uncharge mm/mremap.c:964 [inline]
> >> RIP: 0010:expand_vma_in_place mm/mremap.c:1566 [inline]
> >> RIP: 0010:expand_vma mm/mremap.c:1621 [inline]
> >> RIP: 0010:mremap_at mm/mremap.c:1682 [inline]
> >> RIP: 0010:do_mremap mm/mremap.c:1727 [inline]
> >> RIP: 0010:__do_sys_mremap mm/mremap.c:1784 [inline]
> >> RIP: 0010:__se_sys_mremap+0x25fa/0x2c00 mm/mremap.c:1752
> >> Code: c0 0f 85 0e 05 00 00 0f b6 9c 24 20 03 00 00 31 ff 89 de e8 d8 0d ab ff 85 db 0f 84 7b 01 00 00 e8 cb 0a ab ff e9 9e 00 00 00 <80> 78 04 00 74 0a bf 20 00 00 00 e8 26 2f 15 00 4c 8b 34 25 20 00
> >> RSP: 0018:ffffc900040cfb40 EFLAGS: 00010246
> >> RAX: dffffc0000000000 RBX: 0000000000000000 RCX: 1ffff92000819fca
> >> RDX: 0000000000000000 RSI: 0000000010000000 RDI: 0000000000000000
> >> RBP: ffffc900040cff00 R08: ffffffff821d1f24 R09: ffffffff8c271397
> >> R10: 0000000000000004 R11: ffff888034658000 R12: 0000200000000000
> >> R13: ffff888077fac000 R14: 00000000180000fa R15: ffffc900040cfcd0
> >> FS: 0000555571cf3380(0000) GS:ffff888124f99000(0000) knlGS:0000000000000000
> >> CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> >> CR2: 00002000000000c0 CR3: 00000000316de000 CR4: 00000000003526f0
> >> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> >> DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
> >> Call Trace:
> >> <TASK>
> >> do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
> >> do_syscall_64+0xf3/0x230 arch/x86/entry/syscall_64.c:94
> >> entry_SYSCALL_64_after_hwframe+0x77/0x7f
> >> RIP: 0033:0x7f4480ba0369
> >> 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:00007fff6c642778 EFLAGS: 00000246 ORIG_RAX: 0000000000000019
> >> RAX: ffffffffffffffda RBX: 0000200000000000 RCX: 00007f4480ba0369
> >> RDX: 0000000000004000 RSI: 0000000000001000 RDI: 0000200000000000
> >> RBP: 0000200000001000 R08: 0000200000001000 R09: 0000000000000000
> >> R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001
> >> R13: 00007fff6c642958 R14: 0000000000000001 R15: 0000000000000001
> >> </TASK>
> >> Modules linked in:
> >> ---[ end trace 0000000000000000 ]---
> >> RIP: 0010:vrm_uncharge mm/mremap.c:964 [inline]
> >> RIP: 0010:expand_vma_in_place mm/mremap.c:1566 [inline]
> >> RIP: 0010:expand_vma mm/mremap.c:1621 [inline]
> >> RIP: 0010:mremap_at mm/mremap.c:1682 [inline]
> >> RIP: 0010:do_mremap mm/mremap.c:1727 [inline]
> >> RIP: 0010:__do_sys_mremap mm/mremap.c:1784 [inline]
> >> RIP: 0010:__se_sys_mremap+0x25fa/0x2c00 mm/mremap.c:1752
> >> Code: c0 0f 85 0e 05 00 00 0f b6 9c 24 20 03 00 00 31 ff 89 de e8 d8 0d ab ff 85 db 0f 84 7b 01 00 00 e8 cb 0a ab ff e9 9e 00 00 00 <80> 78 04 00 74 0a bf 20 00 00 00 e8 26 2f 15 00 4c 8b 34 25 20 00
> >> RSP: 0018:ffffc900040cfb40 EFLAGS: 00010246
> >> RAX: dffffc0000000000 RBX: 0000000000000000 RCX: 1ffff92000819fca
> >> RDX: 0000000000000000 RSI: 0000000010000000 RDI: 0000000000000000
> >> RBP: ffffc900040cff00 R08: ffffffff821d1f24 R09: ffffffff8c271397
> >> R10: 0000000000000004 R11: ffff888034658000 R12: 0000200000000000
> >> R13: ffff888077fac000 R14: 00000000180000fa R15: ffffc900040cfcd0
> >> FS: 0000555571cf3380(0000) GS:ffff888124f99000(0000) knlGS:0000000000000000
> >> CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> >> CR2: 00002000000000c0 CR3: 00000000316de000 CR4: 00000000003526f0
> >> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> >> DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
> >> ----------------
> >> Code disassembly (best guess), 1 bytes skipped:
> >> 0: 0f 85 0e 05 00 00 jne 0x514
> >> 6: 0f b6 9c 24 20 03 00 movzbl 0x320(%rsp),%ebx
> >> d: 00
> >> e: 31 ff xor %edi,%edi
> >> 10: 89 de mov %ebx,%esi
> >> 12: e8 d8 0d ab ff call 0xffab0def
> >> 17: 85 db test %ebx,%ebx
> >> 19: 0f 84 7b 01 00 00 je 0x19a
> >> 1f: e8 cb 0a ab ff call 0xffab0aef
> >> 24: e9 9e 00 00 00 jmp 0xc7
> >> * 29: 80 78 04 00 cmpb $0x0,0x4(%rax) <-- trapping instruction
> >> 2d: 74 0a je 0x39
> >> 2f: bf 20 00 00 00 mov $0x20,%edi
> >> 34: e8 26 2f 15 00 call 0x152f5f
> >> 39: 4c rex.WR
> >> 3a: 8b .byte 0x8b
> >> 3b: 34 25 xor $0x25,%al
> >> 3d: 20 00 and %al,(%rax)
> >>
> >>
> >> ---
> >> 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.

Next message: Yeo Reum Yun: "Re: [PATCH v4] coresight: prevent deactivate active config while enabling the config"
Previous message: Francesco Dolcini: "[PATCH v4 1/2] dt-bindings: hwmon: amc6821: add fan and PWM output"
In reply to: syzbot: "Re: [syzbot] [mm?] general protection fault in sys_mremap"
Next in thread: syzbot: "Re: [syzbot] [mm?] general protection fault in sys_mremap"
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