Re: [syzbot] [io-uring?] [mm?] general protection fault in lock_vma_under_rcu

[Shivank Garg <shivankg@amd.com>]

On 2/25/2025 1:40 PM, syzbot wrote:
> Hello,
> 
> syzbot found the following issue on:
> 
> HEAD commit:    e5d3fd687aac Add linux-next specific files for 20250218
> git tree:       linux-next
> console output: https://syzkaller.appspot.com/x/log.txt?x=1643b498580000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=4e945b2fe8e5992f
> dashboard link: https://syzkaller.appspot.com/bug?extid=556fda2d78f9b0daa141
> 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=138207a4580000
> 
> Downloadable assets:
> disk image: https://storage.googleapis.com/syzbot-assets/ef079ccd2725/disk-e5d3fd68.raw.xz
> vmlinux: https://storage.googleapis.com/syzbot-assets/99f2123d6831/vmlinux-e5d3fd68.xz
> kernel image: https://storage.googleapis.com/syzbot-assets/eadfc9520358/bzImage-e5d3fd68.xz
> 
> The issue was bisected to:
> 
> commit 0670f2f4d6ff1cd6aa351389130ba7bbafb02320
> Author: Suren Baghdasaryan <surenb@google.com>
> Date:   Thu Feb 13 22:46:49 2025 +0000
> 
>     mm: replace vm_lock and detached flag with a reference count
> 
> bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=1355bfdf980000
> final oops:     https://syzkaller.appspot.com/x/report.txt?x=10d5bfdf980000
> console output: https://syzkaller.appspot.com/x/log.txt?x=1755bfdf980000
> 
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: syzbot+556fda2d78f9b0daa141@syzkaller.appspotmail.com
> Fixes: 0670f2f4d6ff ("mm: replace vm_lock and detached flag with a reference count")
> 
> Oops: general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] PREEMPT SMP KASAN PTI
> KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
> CPU: 0 UID: 0 PID: 27018 Comm: syz.1.4414 Not tainted 6.14.0-rc3-next-20250218-syzkaller #0
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
> RIP: 0010:vma_refcount_put include/linux/mm.h:712 [inline]
> RIP: 0010:vma_end_read include/linux/mm.h:811 [inline]
> RIP: 0010:lock_vma_under_rcu+0x578/0xac0 mm/memory.c:6454
> Code: be 5d b1 ff 49 be 00 00 00 00 00 fc ff df 4d 85 ff 74 0d 49 81 ff 01 f0 ff ff 0f 82 a3 02 00 00 49 83 ff f5 0f 85 55 03 00 00 <41> 80 3e 00 74 0a bf 05 00 00 00 e8 28 df 18 00 4c 8b 34 25 05 00
> RSP: 0000:ffffc9000b837d80 EFLAGS: 00010246
> RAX: fffffffffffffff5 RBX: 0000000000000000 RCX: ffff888079eb8000
> RDX: ffff888079eb8000 RSI: 0000000000000000 RDI: 0000000000000000
> RBP: ffffc9000b837ed8 R08: ffffffff8210a26a R09: 1ffff110068be328
> R10: dffffc0000000000 R11: ffffed10068be329 R12: ffffc9000b837e10
> R13: ffff88802890aa20 R14: dffffc0000000000 R15: fffffffffffffff5
> FS:  00005555908b1500(0000) GS:ffff8880b8600000(0000) knlGS:0000000000000000
> CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 0000400000002fc0 CR3: 0000000011df6000 CR4: 00000000003526f0
> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
> Call Trace:
>  <TASK>
>  do_user_addr_fault arch/x86/mm/fault.c:1328 [inline]
>  handle_page_fault arch/x86/mm/fault.c:1480 [inline]
>  exc_page_fault+0x17b/0x920 arch/x86/mm/fault.c:1538
>  asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623
> RIP: 0033:0x7f617a954ed8
> Code: fc 89 37 c3 c5 fa 6f 06 c5 fa 6f 4c 16 f0 c5 fa 7f 07 c5 fa 7f 4c 17 f0 c3 66 0f 1f 84 00 00 00 00 00 48 8b 4c 16 f8 48 8b 36 <48> 89 37 48 89 4c 17 f8 c3 c5 fe 6f 54 16 e0 c5 fe 6f 5c 16 c0 c5
> RSP: 002b:00007ffc20f24718 EFLAGS: 00010246
> RAX: 0000400000002fc0 RBX: 0000000000000004 RCX: 0031313230386c6e
> RDX: 0000000000000008 RSI: 0031313230386c6e RDI: 0000400000002fc0
> RBP: 0000000000000000 R08: 00007f617a800000 R09: 0000000000000001
> R10: 0000000000000001 R11: 0000000000000009 R12: 00007f617aba5fac
> R13: 00007f617aba5fa0 R14: fffffffffffffffe R15: 0000000000000006
>  </TASK>
> Modules linked in:
> ---[ end trace 0000000000000000 ]---
> RIP: 0010:vma_refcount_put include/linux/mm.h:712 [inline]
> RIP: 0010:vma_end_read include/linux/mm.h:811 [inline]
> RIP: 0010:lock_vma_under_rcu+0x578/0xac0 mm/memory.c:6454
> Code: be 5d b1 ff 49 be 00 00 00 00 00 fc ff df 4d 85 ff 74 0d 49 81 ff 01 f0 ff ff 0f 82 a3 02 00 00 49 83 ff f5 0f 85 55 03 00 00 <41> 80 3e 00 74 0a bf 05 00 00 00 e8 28 df 18 00 4c 8b 34 25 05 00
> RSP: 0000:ffffc9000b837d80 EFLAGS: 00010246
> RAX: fffffffffffffff5 RBX: 0000000000000000 RCX: ffff888079eb8000
> RDX: ffff888079eb8000 RSI: 0000000000000000 RDI: 0000000000000000
> RBP: ffffc9000b837ed8 R08: ffffffff8210a26a R09: 1ffff110068be328
> R10: dffffc0000000000 R11: ffffed10068be329 R12: ffffc9000b837e10
> R13: ffff88802890aa20 R14: dffffc0000000000 R15: fffffffffffffff5
> FS:  00005555908b1500(0000) GS:ffff8880b8600000(0000) knlGS:0000000000000000
> CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 00007ff182f3cf98 CR3: 0000000011df6000 CR4: 00000000003526f0
> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
> ----------------
> Code disassembly (best guess), 1 bytes skipped:
>    0:	5d                   	pop    %rbp
>    1:	b1 ff                	mov    $0xff,%cl
>    3:	49 be 00 00 00 00 00 	movabs $0xdffffc0000000000,%r14
>    a:	fc ff df
>    d:	4d 85 ff             	test   %r15,%r15
>   10:	74 0d                	je     0x1f
>   12:	49 81 ff 01 f0 ff ff 	cmp    $0xfffffffffffff001,%r15
>   19:	0f 82 a3 02 00 00    	jb     0x2c2
>   1f:	49 83 ff f5          	cmp    $0xfffffffffffffff5,%r15
>   23:	0f 85 55 03 00 00    	jne    0x37e
> * 29:	41 80 3e 00          	cmpb   $0x0,(%r14) <-- trapping instruction
>   2d:	74 0a                	je     0x39
>   2f:	bf 05 00 00 00       	mov    $0x5,%edi
>   34:	e8 28 df 18 00       	call   0x18df61
>   39:	4c                   	rex.WR
>   3a:	8b                   	.byte 0x8b
>   3b:	34 25                	xor    $0x25,%al
>   3d:	05                   	.byte 0x5

Hi, 

This issue is fixed by this patch:
https://lore.kernel.org/all/20250220200208.323769-1-surenb@google.com

#syz fix: mm: fix a crash due to vma_end_read() that should have been removed

Thanks,
Shivank