On Thu, Oct 20, 2022 at 6:22 PM Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> wrote: > > On Thu, 20 Oct 2022 05:40:43 -0700 syzbot <syzbot+b910411d3d253dab25d8@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote: > > > syzbot has found a reproducer for the following issue on: > > Thanks. > > > > HEAD commit: acee3e83b493 Add linux-next specific files for 20221020 > > git tree: linux-next > > console+strace: https://syzkaller.appspot.com/x/log.txt?x=170a8016880000 > > kernel config: https://syzkaller.appspot.com/x/.config?x=c82245cfb913f766 > > dashboard link: https://syzkaller.appspot.com/bug?extid=b910411d3d253dab25d8 > > compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2 > > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=109e0372880000 > > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1770d752880000 > > > > Downloadable assets: > > disk image: https://storage.googleapis.com/syzbot-assets/98cc5896cded/disk-acee3e83.raw.xz > > vmlinux: https://storage.googleapis.com/syzbot-assets/b3d3eb3aa10a/vmlinux-acee3e83.xz > > > > IMPORTANT: if you fix the issue, please add the following tag to the commit: > > Reported-by: syzbot+b910411d3d253dab25d8@xxxxxxxxxxxxxxxxxxxxxxxxx > > > > BUG: sleeping function called from invalid context at include/linux/sched/mm.h:274 > > This is happening under dup_anon_vma_name(). > > I can't spot preemption being disabled on that call path, and I assume > this code has been exercised for some time. Indeed, it is unclear why copy_vma() would be called in atomic context. I'll try to reproduce tomorrow. Maybe with lockdep enabled we can get something interesting. > > I wonder if this could be fallout from the KSM locking error which > https://lkml.kernel.org/r/8c86678a-3bfb-3854-b1a9-ae5969e730b8@xxxxxxxxxx > addresses. Seems quite unlikely. > > > in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 3602, name: syz-executor107 > > preempt_count: 1, expected: 0 > > RCU nest depth: 0, expected: 0 > > INFO: lockdep is turned off. > > Preemption disabled at: > > [<0000000000000000>] 0x0 > > CPU: 0 PID: 3602 Comm: syz-executor107 Not tainted 6.1.0-rc1-next-20221020-syzkaller #0 > > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/22/2022 > > Call Trace: > > <TASK> > > __dump_stack lib/dump_stack.c:88 [inline] > > dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106 > > __might_resched.cold+0x222/0x26b kernel/sched/core.c:9890 > > might_alloc include/linux/sched/mm.h:274 [inline] > > slab_pre_alloc_hook mm/slab.h:727 [inline] > > slab_alloc_node mm/slub.c:3323 [inline] > > slab_alloc mm/slub.c:3411 [inline] > > __kmem_cache_alloc_lru mm/slub.c:3418 [inline] > > kmem_cache_alloc+0x2e6/0x3c0 mm/slub.c:3427 > > vm_area_dup+0x81/0x380 kernel/fork.c:466 > > copy_vma+0x376/0x8d0 mm/mmap.c:3216 > > move_vma+0x449/0xf60 mm/mremap.c:626 > > __do_sys_mremap+0x487/0x16b0 mm/mremap.c:1075 > > do_syscall_x64 arch/x86/entry/common.c:50 [inline] > > do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 > > entry_SYSCALL_64_after_hwframe+0x63/0xcd > > RIP: 0033:0x7fd090fa5b29 > > Code: 28 c3 e8 2a 14 00 00 66 2e 0f 1f 84 00 00 00 00 00 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 c0 ff ff ff f7 d8 64 89 01 48 > > RSP: 002b:00007ffc2e90bd38 EFLAGS: 00000246 ORIG_RAX: 0000000000000019 > > RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fd090fa5b29 > > RDX: 0000000000001000 RSI: 0000000000004000 RDI: 00000000201c4000 > > RBP: 00007fd090f69cd0 R08: 00000000202ef000 R09: 0000000000000000 > > R10: 0000000000000003 R11: 0000000000000246 R12: 00007fd090f69d60 > > R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 > > </TASK>
