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@xxxxxxxxxxxxxxxxxxxxxxxxx > > 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;
