On Wed, Jul 2, 2025 at 2:59 AM syzbot <syzbot+6246a83e7bd9f8a3e239@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote: > > Hello, > > syzbot found the following issue on: > > HEAD commit: 1343433ed389 Add linux-next specific files for 20250630 > git tree: linux-next > console output: https://syzkaller.appspot.com/x/log.txt?x=1243e3d4580000 > kernel config: https://syzkaller.appspot.com/x/.config?x=c1ce97baf6bd6397 > dashboard link: https://syzkaller.appspot.com/bug?extid=6246a83e7bd9f8a3e239 > compiler: Debian clang version 20.1.6 (++20250514063057+1e4d39e07757-1~exp1~20250514183223.118), Debian LLD 20.1.6 > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=11b1b88c580000 > > Downloadable assets: > disk image: https://storage.googleapis.com/syzbot-assets/c3387c64e9ec/disk-1343433e.raw.xz > vmlinux: https://storage.googleapis.com/syzbot-assets/abf15e85d8dd/vmlinux-1343433e.xz > kernel image: https://storage.googleapis.com/syzbot-assets/081c344403bc/bzImage-1343433e.xz > > The issue was bisected to: > > commit 8b877c5aaaaf9b5170928d0e033ea9b0c538fc94 > Author: Suren Baghdasaryan <surenb@xxxxxxxxxx> > Date: Tue Jun 24 19:33:59 2025 +0000 > > mm/maps: execute PROCMAP_QUERY ioctl under per-vma locks > > bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=16095770580000 > final oops: https://syzkaller.appspot.com/x/report.txt?x=15095770580000 > console output: https://syzkaller.appspot.com/x/log.txt?x=11095770580000 > > IMPORTANT: if you fix the issue, please add the following tag to the commit: > Reported-by: syzbot+6246a83e7bd9f8a3e239@xxxxxxxxxxxxxxxxxxxxxxxxx > Fixes: 8b877c5aaaaf ("mm/maps: execute PROCMAP_QUERY ioctl under per-vma locks") > > BUG: sleeping function called from invalid context at ./include/linux/sched/mm.h:321 > in_atomic(): 0, irqs_disabled(): 0, non_block: 0, pid: 6032, name: syz.0.16 > preempt_count: 0, expected: 0 > RCU nest depth: 1, expected: 0 > 2 locks held by syz.0.16/6032: > #0: ffffffff8e13bee0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] > #0: ffffffff8e13bee0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline] > #0: ffffffff8e13bee0 (rcu_read_lock){....}-{1:3}, at: query_vma_setup+0x18/0x110 fs/proc/task_mmu.c:499 > #1: ffff888076dbe308 (vm_lock){++++}-{0:0}, at: lock_next_vma+0x146/0xdc0 mm/mmap_lock.c:220 > CPU: 1 UID: 0 PID: 6032 Comm: syz.0.16 Not tainted 6.16.0-rc4-next-20250630-syzkaller #0 PREEMPT(full) > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 > Call Trace: > <TASK> > dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120 > __might_resched+0x495/0x610 kernel/sched/core.c:8687 > might_alloc include/linux/sched/mm.h:321 [inline] > slab_pre_alloc_hook mm/slub.c:4131 [inline] > slab_alloc_node mm/slub.c:4209 [inline] > __do_kmalloc_node mm/slub.c:4364 [inline] > __kmalloc_noprof+0xbc/0x4f0 mm/slub.c:4377 > kmalloc_noprof include/linux/slab.h:909 [inline] > do_procmap_query fs/proc/task_mmu.c:690 [inline] > procfs_procmap_ioctl+0x877/0xd10 fs/proc/task_mmu.c:748 > vfs_ioctl fs/ioctl.c:51 [inline] > __do_sys_ioctl fs/ioctl.c:907 [inline] > __se_sys_ioctl+0xfc/0x170 fs/ioctl.c:893 > do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] > do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94 > entry_SYSCALL_64_after_hwframe+0x77/0x7f > RIP: 0033:0x7f107ed8e929 > Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48 > RSP: 002b:00007fffd594c468 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 > RAX: ffffffffffffffda RBX: 00007f107efb5fa0 RCX: 00007f107ed8e929 > RDX: 0000200000000180 RSI: 00000000c0686611 RDI: 0000000000000003 > RBP: 00007f107ee10b39 R08: 0000000000000000 R09: 0000000000000000 > R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 > R13: 00007f107efb5fa0 R14: 00007f107efb5fa0 R15: 0000000000000003 > </TASK> I see. There is an allocation inside the new rcu_read section. I think this is easy to fix. We don't need to be in the RCU read section from query_vma_setup() up to query_vma_teardown(). Instead I can narrow it down to query_matching_vma() only since that's the only place we need that. Will post a new version tomorrow that will include this fix. Thanks! > > > --- > 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@xxxxxxxxxxxxxxxx. > > syzbot will keep track of this issue. See: > https://goo.gl/tpsmEJ#status for how to communicate with syzbot. > For information about bisection process see: https://goo.gl/tpsmEJ#bisection > > 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
