| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Message-ID: <fa9d2da7-f547-4731-af84-b4871e588bae@redhat.com> Date: Wed, 20 Nov 2024 19:38:39 +0100 From: David Hildenbrand <david@...hat.com> To: syzbot <syzbot+3511625422f7aa637f0d@...kaller.appspotmail.com>, akpm@...ux-foundation.org, linux-kernel@...r.kernel.org, linux-mm@...ck.org, syzkaller-bugs@...glegroups.com Subject: Re: [syzbot] [mm?] general protection fault in do_migrate_pages On 20.11.24 19:11, David Hildenbrand wrote: > On 20.11.24 17:39, David Hildenbrand wrote: >> On 20.11.24 16:38, David Hildenbrand wrote: >>> On 20.11.24 01:00, syzbot wrote: >>>> Hello, >>>> >>>> syzbot found the following issue on: >>>> >>>> HEAD commit: f868cd251776 Merge tag 'drm-fixes-2024-11-16' of https://g.. >>>> git tree: upstream >>>> console output: https://syzkaller.appspot.com/x/log.txt?x=15473cc0580000 >>>> kernel config: https://syzkaller.appspot.com/x/.config?x=ff8e8187a30080b5 >>>> dashboard link: https://syzkaller.appspot.com/bug?extid=3511625422f7aa637f0d >>>> 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=17e8d130580000 >>>> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=159c71a7980000 >>>> >>>> Downloadable assets: >>>> disk image: https://storage.googleapis.com/syzbot-assets/a0d46da55993/disk-f868cd25.raw.xz >>>> vmlinux: https://storage.googleapis.com/syzbot-assets/da57ef4813fd/vmlinux-f868cd25.xz >>>> kernel image: https://storage.googleapis.com/syzbot-assets/3cdde892ea08/bzImage-f868cd25.xz >>>> >>>> IMPORTANT: if you fix the issue, please add the following tag to the commit: >>>> Reported-by: syzbot+3511625422f7aa637f0d@...kaller.appspotmail.com >>>> >>>> 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: 1 UID: 0 PID: 6021 Comm: syz-executor284 Not tainted 6.12.0-rc7-syzkaller-00187-gf868cd251776 #0 >>>> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/30/2024 >>>> RIP: 0010:migrate_to_node mm/mempolicy.c:1090 [inline] >>>> RIP: 0010:do_migrate_pages+0x403/0x6f0 mm/mempolicy.c:1194 >>>> Code: 8b 54 24 30 41 83 c8 10 80 3a 00 4d 63 c0 0f 85 d1 02 00 00 48 89 c1 48 8b 54 24 18 48 be 00 00 00 00 00 fc ff df 48 c1 e9 03 <80> 3c 31 00 48 8b 92 b0 00 00 00 0f 85 74 02 00 00 48 8b 30 49 89 >>>> RSP: 0018:ffffc9000375fd08 EFLAGS: 00010246 >>>> RAX: 0000000000000000 RBX: ffffc9000375fd78 RCX: 0000000000000000 >>>> RDX: ffff88807e171300 RSI: dffffc0000000000 RDI: ffff88803390c044 >>>> RBP: ffff88807e171428 R08: 0000000000000014 R09: fffffbfff2039ef1 >>>> R10: ffffffff901cf78f R11: 0000000000000000 R12: 0000000000000003 >>>> R13: ffffc9000375fe90 R14: ffffc9000375fe98 R15: ffffc9000375fdf8 >>>> FS: 00005555919e1380(0000) GS:ffff8880b8700000(0000) knlGS:0000000000000000 >>>> CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 >>>> CR2: 00005555919e1ca8 CR3: 000000007f12a000 CR4: 00000000003526f0 >>>> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 >>>> DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 >>>> Call Trace: >>>> <TASK> >>>> kernel_migrate_pages+0x5b2/0x750 mm/mempolicy.c:1709 >>>> __do_sys_migrate_pages mm/mempolicy.c:1727 [inline] >>>> __se_sys_migrate_pages mm/mempolicy.c:1723 [inline] >>>> __x64_sys_migrate_pages+0x96/0x100 mm/mempolicy.c:1723 >>>> do_syscall_x64 arch/x86/entry/common.c:52 [inline] >>>> do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83 >>>> entry_SYSCALL_64_after_hwframe+0x77/0x7f >>>> RIP: 0033:0x7fedcca74af9 >>>> Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 c1 17 00 00 90 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:00007ffe4d85c278 EFLAGS: 00000206 ORIG_RAX: 0000000000000100 >>>> RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fedcca74af9 >>>> RDX: 0000000020000000 RSI: 000000000000005a RDI: 0000000000001786 >>>> RBP: 0000000000010bf2 R08: 0000000000006080 R09: 0000000000000006 >>>> R10: 0000000020000040 R11: 0000000000000206 R12: 00007ffe4d85c28c >>>> R13: 431bde82d7b634db R14: 0000000000000001 R15: 0000000000000001 >>>> </TASK> >>>> Modules linked in: >>>> ---[ end trace 0000000000000000 ]--- >>>> RIP: 0010:migrate_to_node mm/mempolicy.c:1090 [inline] >>>> RIP: 0010:do_migrate_pages+0x403/0x6f0 mm/mempolicy.c:1194 >>>> Code: 8b 54 24 30 41 83 c8 10 80 3a 00 4d 63 c0 0f 85 d1 02 00 00 48 89 c1 48 8b 54 24 18 48 be 00 00 00 00 00 fc ff df 48 c1 e9 03 <80> 3c 31 00 48 8b 92 b0 00 00 00 0f 85 74 02 00 00 48 8b 30 49 89 >>>> RSP: 0018:ffffc9000375fd08 EFLAGS: 00010246 >>>> RAX: 0000000000000000 RBX: ffffc9000375fd78 RCX: 0000000000000000 >>>> RDX: ffff88807e171300 RSI: dffffc0000000000 RDI: ffff88803390c044 >>>> RBP: ffff88807e171428 R08: 0000000000000014 R09: fffffbfff2039ef1 >>>> R10: ffffffff901cf78f R11: 0000000000000000 R12: 0000000000000003 >>>> R13: ffffc9000375fe90 R14: ffffc9000375fe98 R15: ffffc9000375fdf8 >>>> FS: 00005555919e1380(0000) GS:ffff8880b8700000(0000) knlGS:0000000000000000 >>>> CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 >>>> CR2: 00005555919e1ca8 CR3: 000000007f12a000 CR4: 00000000003526f0 >>>> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 >>>> DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 >>>> ---------------- >>>> Code disassembly (best guess): >>>> 0: 8b 54 24 30 mov 0x30(%rsp),%edx >>>> 4: 41 83 c8 10 or $0x10,%r8d >>>> 8: 80 3a 00 cmpb $0x0,(%rdx) >>>> b: 4d 63 c0 movslq %r8d,%r8 >>>> e: 0f 85 d1 02 00 00 jne 0x2e5 >>>> 14: 48 89 c1 mov %rax,%rcx >>>> 17: 48 8b 54 24 18 mov 0x18(%rsp),%rdx >>>> 1c: 48 be 00 00 00 00 00 movabs $0xdffffc0000000000,%rsi >>>> 23: fc ff df >>>> 26: 48 c1 e9 03 shr $0x3,%rcx >>>> * 2a: 80 3c 31 00 cmpb $0x0,(%rcx,%rsi,1) <-- trapping instruction >>>> 2e: 48 8b 92 b0 00 00 00 mov 0xb0(%rdx),%rdx >>>> 35: 0f 85 74 02 00 00 jne 0x2af >>>> 3b: 48 8b 30 mov (%rax),%rsi >>>> 3e: 49 rex.WB >>>> 3f: 89 .byte 0x89 >>>> >>> >>> Hmmm, there is not much meat in this report :) >>> >>> The reproducer seems to execute migrate_pages() in a fork'ed child >>> process, and kills that process after a while. Not 100% sure if the >>> concurrent killing of the process is relevant. >>> >>> Before the child process calls migrate_pages(), it executes >>> MADV_DONTFORK on the complete address space (funny, I wonder what that >>> does ...) and then calls clone3() without CLONE_VM. >>> >> >> After running it for a while in a VM with the given config: >> >> [ 827.514143][T37171] Oops: general protection fault, probably for >> non-canonical address 0xdffffc0000000000: 0000 [#1] PREEMPT SMP KASAN NOPTI >> [ 827.516614][T37171] KASAN: null-ptr-deref in range >> [0x0000000000000000-0x0000000000000007] >> [ 827.518162][T37171] CPU: 4 UID: 0 PID: 37171 Comm: repro4 Not tainted >> 6.12.0-rc7-00187-gf868cd251776 #99 >> [ 827.519935][T37171] Hardware name: QEMU Standard PC (Q35 + ICH9, >> 2009), BIOS 1.16.3-2.fc40 04/01/2014 >> [ 827.521648][T37171] RIP: 0010:do_migrate_pages+0x404/0x6e0 >> [ 827.522774][T37171] Code: 10 80 39 00 4d 63 c0 0f 85 9b 02 00 00 48 >> be 00 00 00 00 00 fc ff df 48 8b 4c 24 28 48 8b 91 b0 00 00 00 48 89 c1 >> 48 c1 e9 03 <80> 3c 31 00 0f 85 95 02 00 00 48 8b 30 49 89 d9 48 8b 4c >> 24 08 48 >> [ 827.526342][T37171] RSP: 0018:ffffc90028157ce8 EFLAGS: 00010256 >> [ 827.527480][T37171] RAX: 0000000000000000 RBX: ffffc90028157d68 RCX: >> 0000000000000000 >> [ 827.528942][T37171] RDX: 00007ffffffff000 RSI: dffffc0000000000 RDI: >> ffff88811dcd8444 >> [ 827.530406][T37171] RBP: 0000000000000003 R08: 0000000000000014 R09: >> ffff88811dcd8ad8 >> [ 827.531865][T37171] R10: ffffffff903e668f R11: 0000000000000000 R12: >> ffffc90028157e80 >> [ 827.533341][T37171] R13: ffff8881f3a2b0a8 R14: ffffc90028157e28 R15: >> ffffc90028157e88 >> [ 827.534806][T37171] FS: 00007f096d49f740(0000) >> GS:ffff8881f4a00000(0000) knlGS:0000000000000000 >> [ 827.536452][T37171] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 >> [ 827.537672][T37171] CR2: 00007ff2dcb96810 CR3: 00000001eed18000 CR4: >> 0000000000750ef0 >> [ 827.539135][T37171] PKRU: 55555554 >> [ 827.539799][T37171] Call Trace: >> [ 827.540407][T37171] <TASK> >> [ 827.540965][T37171] ? die_addr.cold+0x8/0xd >> [ 827.541823][T37171] ? exc_general_protection+0x147/0x240 >> [ 827.542888][T37171] ? asm_exc_general_protection+0x26/0x30 >> [ 827.543960][T37171] ? do_migrate_pages+0x404/0x6e0 >> [ 827.544915][T37171] ? do_migrate_pages+0x3cd/0x6e0 >> [ 827.545873][T37171] ? __pfx_do_migrate_pages+0x10/0x10 >> [ 827.546895][T37171] ? do_raw_spin_lock+0x12a/0x2b0 >> [ 827.547854][T37171] ? apparmor_capable+0x11c/0x3b0 >> [ 827.548818][T37171] ? srso_alias_return_thunk+0x5/0xfbef5 >> [ 827.549878][T37171] ? srso_alias_return_thunk+0x5/0xfbef5 >> [ 827.550937][T37171] ? security_capable+0x80/0x260 >> [ 827.551893][T37171] kernel_migrate_pages+0x5b7/0x750 >> [ 827.552891][T37171] ? __pfx_kernel_migrate_pages+0x10/0x10 >> [ 827.553975][T37171] ? srso_alias_return_thunk+0x5/0xfbef5 >> [ 827.555028][T37171] ? rcu_is_watching+0x12/0xc0 >> [ 827.555938][T37171] ? srso_alias_return_thunk+0x5/0xfbef5 >> [ 827.557000][T37171] __x64_sys_migrate_pages+0x96/0x100 >> [ 827.558022][T37171] ? srso_alias_return_thunk+0x5/0xfbef5 >> [ 827.559077][T37171] ? lockdep_hardirqs_on+0x7b/0x110 >> [ 827.560052][T37171] do_syscall_64+0xc7/0x250 >> [ 827.560909][T37171] entry_SYSCALL_64_after_hwframe+0x77/0x7f > > .. digging further, we call migrate_pages() with the pid of a process > we created using clone3(!CLONE_VM). > > The crashing code is likely: > > vma = find_vma(mm, 0); > 722c: e8 00 00 00 00 call 7231 <do_migrate_pages+0x3c1> > 7231: 48 8b 7c 24 28 mov 0x28(%rsp),%rdi > 7236: 31 f6 xor %esi,%esi > 7238: e8 00 00 00 00 call 723d <do_migrate_pages+0x3cd> > flags | MPOL_MF_DISCONTIG_OK, &pagelist); > 723d: 44 8b 44 24 3c mov 0x3c(%rsp),%r8d > nr_failed = queue_pages_range(mm, vma->vm_start, mm->task_size, &nmask, > 7242: 48 8b 4c 24 40 mov 0x40(%rsp),%rcx > flags | MPOL_MF_DISCONTIG_OK, &pagelist); > 7247: 41 83 c8 10 or $0x10,%r8d > nr_failed = queue_pages_range(mm, vma->vm_start, mm->task_size, &nmask, > 724b: 80 39 00 cmpb $0x0,(%rcx) > 724e: 4d 63 c0 movslq %r8d,%r8 > 7251: 0f 85 9b 02 00 00 jne 74f2 <do_migrate_pages+0x682> > 7257: 48 be 00 00 00 00 00 movabs $0xdffffc0000000000,%rsi > 725e: fc ff df > 7261: 48 8b 4c 24 28 mov 0x28(%rsp),%rcx > 7266: 48 8b 91 b0 00 00 00 mov 0xb0(%rcx),%rdx > 726d: 48 89 c1 mov %rax,%rcx > 7270: 48 c1 e9 03 shr $0x3,%rcx > 7274: 80 3c 31 00 cmpb $0x0,(%rcx,%rsi,1) > > <--- we seem toc rash here > > 7278: 0f 85 95 02 00 00 jne 7513 <do_migrate_pages+0x6a3> > 727e: 48 8b 30 mov (%rax),%rsi > 7281: 49 89 d9 mov %rbx,%r9 > 7284: 48 8b 4c 24 08 mov 0x8(%rsp),%rcx > 7289: 48 8b 7c 24 28 mov 0x28(%rsp),%rdi > 728e: e8 8d 9a ff ff call d20 <queue_pages_range> > 7293: 48 89 44 24 30 mov %rax,0x30(%rsp) > 7298: e9 c4 00 00 00 jmp 7361 <do_migrate_pages+0x4f1> > up_read(&mm->mmap_lock); > 729d: e8 00 00 00 00 call 72a2 <do_migrate_pages+0x432> > 72a2: 4c 89 ef mov %r13,%rdi > 72a5: e8 00 00 00 00 call 72aa <do_migrate_pages+0x43a> > > > Which would be do_migrate_pages()->migrate_to_node(): > > mmap_read_lock(mm); > vma = find_vma(mm, 0); > nr_failed = queue_pages_range(mm, vma->vm_start, mm->task_size, &nmask, > flags | MPOL_MF_DISCONTIG_OK, &pagelist); > mmap_read_unlock(mm); > > ... and it seems to fail before calling queue_pages_range() :/ > > Did we, for some reason get a vma=NULL, because someone is concurrently tearing down the MM? I think that's exactly what's happening. Will send a fix after testing it. -- Cheers, David / dhildenb
Powered by blists - more mailing lists