Messages in this thread | | | Subject | Re: BUG: sleeping function called from invalid context in __alloc_pages_nodemask | From | Tetsuo Handa <> | Date | Sat, 30 Nov 2019 20:50:16 +0900 |
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On 2019/11/30 17:32, Hillf Danton wrote: > > On Fri, 29 Nov 2019 23:35:08 -0800 >> Hello, >> >> syzbot found the following crash on: >> >> HEAD commit: 419593da Add linux-next specific files for 20191129 >> git tree: linux-next >> console output: https://syzkaller.appspot.com/x/log.txt?x=12cc369ce00000 >> kernel config: https://syzkaller.appspot.com/x/.config?x=7c04b0959e75c206 >> dashboard link: https://syzkaller.appspot.com/bug?extid=4925d60532bf4c399608 >> compiler: gcc (GCC) 9.0.0 20181231 (experimental) >> >> Unfortunately, I don't have any reproducer for this crash yet. >> >> IMPORTANT: if you fix the bug, please add the following tag to the commit: >> Reported-by: syzbot+4925d60532bf4c399608@syzkaller.appspotmail.com >> >> BUG: sleeping function called from invalid context at mm/page_alloc.c:4681 >> in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 2710, name: >> kworker/0:2 >> 4 locks held by kworker/0:2/2710: >> #0: ffff8880aa026d28 ((wq_completion)events){+.+.}, at: __write_once_size >> include/linux/compiler.h:247 [inline] >> #0: ffff8880aa026d28 ((wq_completion)events){+.+.}, at: arch_atomic64_set >> arch/x86/include/asm/atomic64_64.h:34 [inline] >> #0: ffff8880aa026d28 ((wq_completion)events){+.+.}, at: atomic64_set >> include/asm-generic/atomic-instrumented.h:868 [inline] >> #0: ffff8880aa026d28 ((wq_completion)events){+.+.}, at: atomic_long_set >> include/asm-generic/atomic-long.h:40 [inline] >> #0: ffff8880aa026d28 ((wq_completion)events){+.+.}, at: set_work_data >> kernel/workqueue.c:615 [inline] >> #0: ffff8880aa026d28 ((wq_completion)events){+.+.}, at: >> set_work_pool_and_clear_pending kernel/workqueue.c:642 [inline] >> #0: ffff8880aa026d28 ((wq_completion)events){+.+.}, at: >> process_one_work+0x88b/0x1740 kernel/workqueue.c:2235 >> #1: ffffc9000802fdc0 (pcpu_balance_work){+.+.}, at: >> process_one_work+0x8c1/0x1740 kernel/workqueue.c:2239 >> #2: ffffffff8983ff20 (pcpu_alloc_mutex){+.+.}, at: >> pcpu_balance_workfn+0xb7/0x1310 mm/percpu.c:1845 >> #3: ffffffff89851b18 (vmap_area_lock){+.+.}, at: spin_lock >> include/linux/spinlock.h:338 [inline] >> #3: ffffffff89851b18 (vmap_area_lock){+.+.}, at: >> pcpu_get_vm_areas+0x3b27/0x3f00 mm/vmalloc.c:3431 >> Preemption disabled at: >> [<ffffffff81a89ce7>] spin_lock include/linux/spinlock.h:338 [inline] >> [<ffffffff81a89ce7>] pcpu_get_vm_areas+0x3b27/0x3f00 mm/vmalloc.c:3431 >> CPU: 0 PID: 2710 Comm: kworker/0:2 Not tainted >> 5.4.0-next-20191129-syzkaller #0 >> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS >> Google 01/01/2011 >> Workqueue: events pcpu_balance_workfn >> Call Trace: >> __dump_stack lib/dump_stack.c:77 [inline] >> dump_stack+0x197/0x210 lib/dump_stack.c:118 >> ___might_sleep.cold+0x1fb/0x23e kernel/sched/core.c:6800 >> __might_sleep+0x95/0x190 kernel/sched/core.c:6753 >> prepare_alloc_pages mm/page_alloc.c:4681 [inline] >> __alloc_pages_nodemask+0x523/0x910 mm/page_alloc.c:4730 >> alloc_pages_current+0x107/0x210 mm/mempolicy.c:2211 >> alloc_pages include/linux/gfp.h:532 [inline] >> __get_free_pages+0xc/0x40 mm/page_alloc.c:4786 >> kasan_populate_vmalloc_pte mm/kasan/common.c:762 [inline] >> kasan_populate_vmalloc_pte+0x2f/0x1c0 mm/kasan/common.c:753 >> apply_to_pte_range mm/memory.c:2041 [inline] >> apply_to_pmd_range mm/memory.c:2068 [inline] >> apply_to_pud_range mm/memory.c:2088 [inline] >> apply_to_p4d_range mm/memory.c:2108 [inline] >> apply_to_page_range+0x445/0x700 mm/memory.c:2133 >> kasan_populate_vmalloc+0x68/0x90 mm/kasan/common.c:791 >> pcpu_get_vm_areas+0x3c77/0x3f00 mm/vmalloc.c:3439 >> pcpu_create_chunk+0x24e/0x7f0 mm/percpu-vm.c:340 >> pcpu_balance_workfn+0xf1b/0x1310 mm/percpu.c:1934 >> process_one_work+0x9af/0x1740 kernel/workqueue.c:2264 >> worker_thread+0x98/0xe40 kernel/workqueue.c:2410 >> kthread+0x361/0x430 kernel/kthread.c:255 >> ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352 > > Replace the blocking gfp mask with a non-blocking one to survive > checks like might_sleep. > > --- a/mm/kasan/common.c > +++ b/mm/kasan/common.c > @@ -759,7 +759,7 @@ static int kasan_populate_vmalloc_pte(pt > if (likely(!pte_none(*ptep))) > return 0; > > - page = __get_free_page(GFP_KERNEL); > + page = __get_free_page(GFP_NOWAIT); > if (!page) > return -ENOMEM; >
Nope. This change would survive might_sleep() check, but the caller is expecting that this is __GFP_NOFAIL allocation. Even if the caller can tolerate allocation failures, __GFP_NOWARN should be added in order to avoid flooding of allocation failure messages.
/* insert all vm's */ spin_lock(&vmap_area_lock); for (area = 0; area < nr_vms; area++) { insert_vmap_area(vas[area], &vmap_area_root, &vmap_area_list);
setup_vmalloc_vm_locked(vms[area], vas[area], VM_ALLOC, pcpu_get_vm_areas);
/* assume success here */ kasan_populate_vmalloc(sizes[area], vms[area]); } spin_unlock(&vmap_area_lock);
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