Message-ID: <b9a674c1-860c-4448-aeb2-bf07a78c6fbf@suse.cz>
Date: Mon, 4 Nov 2024 12:25:03 +0100
From: Vlastimil Babka <vbabka@...e.cz>
To: syzbot <syzbot+39f85d612b7c20d8db48@...kaller.appspotmail.com>,
 Liam.Howlett@...cle.com, akpm@...ux-foundation.org, jannh@...gle.com,
 linux-kernel@...r.kernel.org, linux-mm@...ck.org,
 lorenzo.stoakes@...cle.com, syzkaller-bugs@...glegroups.com,
 Sebastian Andrzej Siewior <bigeasy@...utronix.de>,
 Marco Elver <elver@...gle.com>, Andrey Konovalov <andreyknvl@...il.com>,
 kasan-dev <kasan-dev@...glegroups.com>,
 Andrey Ryabinin <ryabinin.a.a@...il.com>,
 Alexander Potapenko <glider@...gle.com>,
 Peter Zijlstra <peterz@...radead.org>, Waiman Long <longman@...hat.com>
Subject: Re: [syzbot] [mm?] WARNING: locking bug in __rmqueue_pcplist

On 11/4/24 12:11, Vlastimil Babka wrote:
> On 11/3/24 11:46, syzbot wrote:
>> Hello,
>> 
>> syzbot found the following issue on:
>> 
>> HEAD commit:    f9f24ca362a4 Add linux-next specific files for 20241031
>> git tree:       linux-next
>> console output: https://syzkaller.appspot.com/x/log.txt?x=1648155f980000
>> kernel config:  https://syzkaller.appspot.com/x/.config?x=328572ed4d152be9
>> dashboard link: https://syzkaller.appspot.com/bug?extid=39f85d612b7c20d8db48
>> 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=16806e87980000
>> 
>> Downloadable assets:
>> disk image: https://storage.googleapis.com/syzbot-assets/eb84549dd6b3/disk-f9f24ca3.raw.xz
>> vmlinux: https://storage.googleapis.com/syzbot-assets/beb29bdfa297/vmlinux-f9f24ca3.xz
>> kernel image: https://storage.googleapis.com/syzbot-assets/8881fe3245ad/bzImage-f9f24ca3.xz
>> 
>> IMPORTANT: if you fix the issue, please add the following tag to the commit:
>> Reported-by: syzbot+39f85d612b7c20d8db48@...kaller.appspotmail.com
>> 
>> =============================
>> [ BUG: Invalid wait context ]
>> 6.12.0-rc5-next-20241031-syzkaller #0 Not tainted
>> -----------------------------
>> syz.0.49/6178 is trying to lock:
>> ffff88813fffc298 (&zone->lock){-.-.}-{3:3}, at: rmqueue_bulk mm/page_alloc.c:2328 [inline]
>> ffff88813fffc298 (&zone->lock){-.-.}-{3:3}, at: __rmqueue_pcplist+0x4c6/0x2b70 mm/page_alloc.c:3022
>> other info that might help us debug this:
>> context-{2:2}
> 
> Seems like another fallout of
> 560af5dc839e ("lockdep: Enable PROVE_RAW_LOCK_NESTING with PROVE_LOCKING")
> 
>> 4 locks held by syz.0.49/6178:
>>  #0: ffff888031745be0 (&mm->mmap_lock){++++}-{4:4}, at: mmap_read_lock include/linux/mmap_lock.h:189 [inline]
>>  #0: ffff888031745be0 (&mm->mmap_lock){++++}-{4:4}, at: exit_mmap+0x165/0xcb0 mm/mmap.c:1677
>>  #1: ffffffff8e939f20 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:337 [inline]
>>  #1: ffffffff8e939f20 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
>>  #1: ffffffff8e939f20 (rcu_read_lock){....}-{1:3}, at: __pte_offset_map+0x82/0x380 mm/pgtable-generic.c:287
>>  #2: ffff88803007c978 (ptlock_ptr(ptdesc)#2){+.+.}-{3:3}, at: spin_lock include/linux/spinlock.h:351 [inline]
>>  #2: ffff88803007c978 (ptlock_ptr(ptdesc)#2){+.+.}-{3:3}, at: __pte_offset_map_lock+0x1ba/0x300 mm/pgtable-generic.c:402
>>  #3: ffff8880b8744618 (&pcp->lock){+.+.}-{3:3}, at: spin_trylock include/linux/spinlock.h:361 [inline]
>>  #3: ffff8880b8744618 (&pcp->lock){+.+.}-{3:3}, at: rmqueue_pcplist mm/page_alloc.c:3051 [inline]
>>  #3: ffff8880b8744618 (&pcp->lock){+.+.}-{3:3}, at: rmqueue mm/page_alloc.c:3095 [inline]
>>  #3: ffff8880b8744618 (&pcp->lock){+.+.}-{3:3}, at: get_page_from_freelist+0x7e2/0x3870 mm/page_alloc.c:3492
>> stack backtrace:
>> CPU: 1 UID: 0 PID: 6178 Comm: syz.0.49 Not tainted 6.12.0-rc5-next-20241031-syzkaller #0
>> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
>> Call Trace:
>>  <IRQ>
>>  __dump_stack lib/dump_stack.c:94 [inline]
>>  dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120
>>  print_lock_invalid_wait_context kernel/locking/lockdep.c:4826 [inline]
>>  check_wait_context kernel/locking/lockdep.c:4898 [inline]
>>  __lock_acquire+0x15a8/0x2100 kernel/locking/lockdep.c:5176
>>  lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5849
>>  __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
>>  _raw_spin_lock_irqsave+0xd5/0x120 kernel/locking/spinlock.c:162
>>  rmqueue_bulk mm/page_alloc.c:2328 [inline]
>>  __rmqueue_pcplist+0x4c6/0x2b70 mm/page_alloc.c:3022
>>  rmqueue_pcplist mm/page_alloc.c:3064 [inline]
>>  rmqueue mm/page_alloc.c:3095 [inline]
>>  get_page_from_freelist+0x895/0x3870 mm/page_alloc.c:3492
>>  __alloc_pages_noprof+0x292/0x710 mm/page_alloc.c:4771
>>  alloc_pages_mpol_noprof+0x3e8/0x680 mm/mempolicy.c:2265
>>  stack_depot_save_flags+0x666/0x830 lib/stackdepot.c:627
>>  save_stack+0x109/0x1f0 mm/page_owner.c:157
>>  __set_page_owner+0x92/0x800 mm/page_owner.c:320
>>  set_page_owner include/linux/page_owner.h:32 [inline]
>>  post_alloc_hook+0x1f3/0x230 mm/page_alloc.c:1541
>>  prep_new_page mm/page_alloc.c:1549 [inline]
>>  get_page_from_freelist+0x3725/0x3870 mm/page_alloc.c:3495
>>  __alloc_pages_noprof+0x292/0x710 mm/page_alloc.c:4771
>>  alloc_pages_mpol_noprof+0x3e8/0x680 mm/mempolicy.c:2265
>>  stack_depot_save_flags+0x666/0x830 lib/stackdepot.c:627
>>  kasan_save_stack+0x4f/0x60 mm/kasan/common.c:48
>>  __kasan_record_aux_stack+0xac/0xc0 mm/kasan/generic.c:544
>>  task_work_add+0xd9/0x490 kernel/task_work.c:77
> 
> It seems the decision if stack depot is allowed to allocate here depends on
> TWAF_NO_ALLOC added only recently. So does it mean it doesn't work as intended?

I guess __run_posix_cpu_timers() needs to pass TWAF_NO_ALLOC too?

> 
>>  __run_posix_cpu_timers kernel/time/posix-cpu-timers.c:1219 [inline]
>>  run_posix_cpu_timers+0x6ac/0x810 kernel/time/posix-cpu-timers.c:1418
>>  tick_sched_handle kernel/time/tick-sched.c:276 [inline]
>>  tick_nohz_handler+0x37c/0x500 kernel/time/tick-sched.c:297
>>  __run_hrtimer kernel/time/hrtimer.c:1691 [inline]
>>  __hrtimer_run_queues+0x551/0xd50 kernel/time/hrtimer.c:1755
>>  hrtimer_interrupt+0x396/0x990 kernel/time/hrtimer.c:1817
>>  local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1038 [inline]
>>  __sysvec_apic_timer_interrupt+0x110/0x420 arch/x86/kernel/apic/apic.c:1055
>>  instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1049 [inline]
>>  sysvec_apic_timer_interrupt+0x52/0xc0 arch/x86/kernel/apic/apic.c:1049
>>  asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
>> RIP: 0010:variable_ffs arch/x86/include/asm/bitops.h:321 [inline]
>> RIP: 0010:handle_softirqs+0x1e3/0x980 kernel/softirq.c:542
>> Code: 7c 24 70 45 0f b7 e4 48 c7 c7 20 c5 09 8c e8 c4 6c 6c 0a 65 66 c7 05 32 53 ac 7e 00 00 e8 05 67 45 00 fb 49 c7 c6 c0 a0 60 8e <b8> ff ff ff ff 41 0f bc c4 41 89 c7 41 ff c7 0f 84 eb 03 00 00 44
>> RSP: 0018:ffffc90000a18e40 EFLAGS: 00000286
>> RAX: 959a1636e72c7c00 RBX: ffffc90000a18ee0 RCX: ffffffff8170c69a
>> RDX: dffffc0000000000 RSI: ffffffff8c0ad3a0 RDI: ffffffff8c604dc0
>> RBP: ffffc90000a18f50 R08: ffffffff942cd847 R09: 1ffffffff2859b08
>> R10: dffffc0000000000 R11: fffffbfff2859b09 R12: 0000000000000010
>> R13: 0000000000000000 R14: ffffffff8e60a0c0 R15: 1ffff11003cec000
>>  __do_softirq kernel/softirq.c:588 [inline]
>>  invoke_softirq kernel/softirq.c:428 [inline]
>>  __irq_exit_rcu+0xf4/0x1c0 kernel/softirq.c:637
>>  irq_exit_rcu+0x9/0x30 kernel/softirq.c:649
>>  common_interrupt+0xb9/0xd0 arch/x86/kernel/irq.c:278
>>  </IRQ>
>>  <TASK>
>>  asm_common_interrupt+0x26/0x40 arch/x86/include/asm/idtentry.h:693
>> RIP: 0010:zap_pmd_range mm/memory.c:1753 [inline]
>> RIP: 0010:zap_pud_range mm/memory.c:1782 [inline]
>> RIP: 0010:zap_p4d_range mm/memory.c:1803 [inline]
>> RIP: 0010:unmap_page_range+0x1ffd/0x4230 mm/memory.c:1824
>> Code: 02 00 00 4c 8d bc 24 c0 02 00 00 48 8b 44 24 48 48 98 48 89 c1 48 c1 e1 0c 49 01 cd 4c 3b ac 24 98 00 00 00 0f 84 44 14 00 00 <4c> 89 6c 24 28 48 8b 5c 24 38 48 8d 1c c3 e8 50 01 b2 ff e9 ec e9
>> RSP: 0018:ffffc9000303f560 EFLAGS: 00000287
>> RAX: 0000000000000001 RBX: ffff88803023b5c8 RCX: 0000000000001000
>> RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
>> RBP: ffffc9000303f890 R08: ffffffff81e30b9c R09: 1ffffd4000333df6
>> R10: dffffc0000000000 R11: fffff94000333df7 R12: dffffc0000000000
>> R13: 00000000200ba000 R14: ffffc9000303f7e0 R15: ffffc9000303f820
>>  unmap_vmas+0x3cc/0x5f0 mm/memory.c:1914
>>  exit_mmap+0x292/0xcb0 mm/mmap.c:1693
>>  __mmput+0x115/0x390 kernel/fork.c:1344
>>  exit_mm+0x220/0x310 kernel/exit.c:570
>>  do_exit+0x9b2/0x28e0 kernel/exit.c:925
>>  do_group_exit+0x207/0x2c0 kernel/exit.c:1087
>>  __do_sys_exit_group kernel/exit.c:1098 [inline]
>>  __se_sys_exit_group kernel/exit.c:1096 [inline]
>>  __x64_sys_exit_group+0x3f/0x40 kernel/exit.c:1096
>>  x64_sys_call+0x2634/0x2640 arch/x86/include/generated/asm/syscalls_64.h:232
>>  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: 0033:0x7faae5f7e719
>> Code: Unable to access opcode bytes at 0x7faae5f7e6ef.
>> RSP: 002b:00007ffc97dbc998 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
>> RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007faae5f7e719
>> RDX: 0000000000000064 RSI: 0000000000000000 RDI: 0000000000000000
>> RBP: 00007ffc97dbc9ec R08: 00007ffc97dbca7f R09: 0000000000013547
>> R10: 0000000000000001 R11: 0000000000000246 R12: 0000000000000032
>> R13: 0000000000013547 R14: 0000000000013547 R15: 00007ffc97dbca40
>>  </TASK>
>> ----------------
>> Code disassembly (best guess):
>>    0:	7c 24                	jl     0x26
>>    2:	70 45                	jo     0x49
>>    4:	0f b7 e4             	movzwl %sp,%esp
>>    7:	48 c7 c7 20 c5 09 8c 	mov    $0xffffffff8c09c520,%rdi
>>    e:	e8 c4 6c 6c 0a       	call   0xa6c6cd7
>>   13:	65 66 c7 05 32 53 ac 	movw   $0x0,%gs:0x7eac5332(%rip)        # 0x7eac534f
>>   1a:	7e 00 00
>>   1d:	e8 05 67 45 00       	call   0x456727
>>   22:	fb                   	sti
>>   23:	49 c7 c6 c0 a0 60 8e 	mov    $0xffffffff8e60a0c0,%r14
>> * 2a:	b8 ff ff ff ff       	mov    $0xffffffff,%eax <-- trapping instruction
>>   2f:	41 0f bc c4          	bsf    %r12d,%eax
>>   33:	41 89 c7             	mov    %eax,%r15d
>>   36:	41 ff c7             	inc    %r15d
>>   39:	0f 84 eb 03 00 00    	je     0x42a
>>   3f:	44                   	rex.R
>> 
>> 
>> ---
>> 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@...glegroups.com.
>> 
>> 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
> 

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