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AJvYcCWC8sdHqvMleFyGSD0wc+Xa89A8Xw+eYdBOlNeR6UIXdP5yKiEOwEH27hLhP/yss7/r4fHXutpa3hMHmb8=@vger.kernel.org X-Gm-Message-State: AOJu0YwGS4RYiYxcXlW8z8RmKqCcxUPF2MPQGSC6oUR1/t1n29fiKXQv U1Srjw7c7TPftC4glUqTEOT04AK/4fbjuWEgy2T6FkDvrqRpxbqf/vbf31Ls1mZ2GEi76SIwslR pivup9Cooi4Y7c75K+GttIOm4Cp+5ewdpXACmudfaDX90V5N5E4PUkyVQt/c= X-Google-Smtp-Source: AGHT+IGxv3OKeAhsNMGG3ZcxHHqsJgQMLneAUR/N4UE0K0dxGV3pqhz/YTgQNtSoCHuX7519tj9SUygrQSglFclpzxXQ6Y1SP5Qt Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Received: by 2002:a05:6602:6b0d:b0:876:8bf2:e4d2 with SMTP id ca18e2360f4ac-879787a2806mr1578319039f.2.1752511113633; Mon, 14 Jul 2025 09:38:33 -0700 (PDT) Date: Mon, 14 Jul 2025 09:38:33 -0700 In-Reply-To: <6871f94b.a00a0220.26a83e.0070.GAE@google.com> X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <68753289.a70a0220.18f9d4.0003.GAE@google.com> Subject: Re: [syzbot] [mm?] possible deadlock in lock_next_vma From: syzbot To: Liam.Howlett@oracle.com, akpm@linux-foundation.org, liam.howlett@oracle.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org, lorenzo.stoakes@oracle.com, shakeel.butt@linux.dev, surenb@google.com, syzkaller-bugs@googlegroups.com, vbabka@suse.cz Content-Type: text/plain; charset="UTF-8" syzbot has found a reproducer for the following issue on: HEAD commit: 0be23810e32e Add linux-next specific files for 20250714 git tree: linux-next console output: https://syzkaller.appspot.com/x/log.txt?x=15cfb0f0580000 kernel config: https://syzkaller.appspot.com/x/.config?x=be9e2082003f81ff dashboard link: https://syzkaller.appspot.com/bug?extid=159a3ef1894076a6a6e9 compiler: Debian clang version 20.1.7 (++20250616065708+6146a88f6049-1~exp1~20250616065826.132), Debian LLD 20.1.7 syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1003b18c580000 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=11437d82580000 Downloadable assets: disk image: https://storage.googleapis.com/syzbot-assets/69e6cc49d526/disk-0be23810.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/71d1bab88eaa/vmlinux-0be23810.xz kernel image: https://storage.googleapis.com/syzbot-assets/5a516dc7bb0d/bzImage-0be23810.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+159a3ef1894076a6a6e9@syzkaller.appspotmail.com ====================================================== WARNING: possible circular locking dependency detected 6.16.0-rc6-next-20250714-syzkaller #0 Not tainted ------------------------------------------------------ syz.2.103/6308 is trying to acquire lock: ffff88807d33bde0 (&mm->mmap_lock){++++}-{4:4}, at: mmap_read_lock_killable include/linux/mmap_lock.h:432 [inline] ffff88807d33bde0 (&mm->mmap_lock){++++}-{4:4}, at: lock_vma_under_mmap_lock mm/mmap_lock.c:189 [inline] ffff88807d33bde0 (&mm->mmap_lock){++++}-{4:4}, at: lock_next_vma+0x802/0xdc0 mm/mmap_lock.c:264 but task is already holding lock: ffff8880338c6948 (vm_lock){++++}-{0:0}, at: lock_next_vma+0x146/0xdc0 mm/mmap_lock.c:220 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (vm_lock){++++}-{0:0}: lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5871 __vma_enter_locked+0x182/0x380 mm/mmap_lock.c:63 __vma_start_write+0x1e/0x120 mm/mmap_lock.c:87 vma_start_write include/linux/mmap_lock.h:267 [inline] mprotect_fixup+0x571/0x9b0 mm/mprotect.c:670 setup_arg_pages+0x53a/0xaa0 fs/exec.c:670 load_elf_binary+0xb9f/0x2730 fs/binfmt_elf.c:1013 search_binary_handler fs/exec.c:1670 [inline] exec_binprm fs/exec.c:1702 [inline] bprm_execve+0x999/0x1450 fs/exec.c:1754 kernel_execve+0x8f0/0x9f0 fs/exec.c:1920 try_to_run_init_process+0x13/0x60 init/main.c:1397 kernel_init+0xad/0x1d0 init/main.c:1525 ret_from_fork+0x3f9/0x770 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 -> #0 (&mm->mmap_lock){++++}-{4:4}: check_prev_add kernel/locking/lockdep.c:3168 [inline] check_prevs_add kernel/locking/lockdep.c:3287 [inline] validate_chain+0xb9b/0x2140 kernel/locking/lockdep.c:3911 __lock_acquire+0xab9/0xd20 kernel/locking/lockdep.c:5240 lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5871 down_read_killable+0x50/0x350 kernel/locking/rwsem.c:1562 mmap_read_lock_killable include/linux/mmap_lock.h:432 [inline] lock_vma_under_mmap_lock mm/mmap_lock.c:189 [inline] lock_next_vma+0x802/0xdc0 mm/mmap_lock.c:264 get_next_vma fs/proc/task_mmu.c:182 [inline] query_vma_find_by_addr fs/proc/task_mmu.c:512 [inline] query_matching_vma+0x319/0x5c0 fs/proc/task_mmu.c:544 do_procmap_query fs/proc/task_mmu.c:629 [inline] procfs_procmap_ioctl+0x3f9/0xd50 fs/proc/task_mmu.c:747 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:598 [inline] __se_sys_ioctl+0xfc/0x170 fs/ioctl.c:584 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 other info that might help us debug this: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- rlock(vm_lock); lock(&mm->mmap_lock); lock(vm_lock); rlock(&mm->mmap_lock); *** DEADLOCK *** 1 lock held by syz.2.103/6308: #0: ffff8880338c6948 (vm_lock){++++}-{0:0}, at: lock_next_vma+0x146/0xdc0 mm/mmap_lock.c:220 stack backtrace: CPU: 0 UID: 0 PID: 6308 Comm: syz.2.103 Not tainted 6.16.0-rc6-next-20250714-syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 Call Trace: dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120 print_circular_bug+0x2ee/0x310 kernel/locking/lockdep.c:2046 check_noncircular+0x134/0x160 kernel/locking/lockdep.c:2178 check_prev_add kernel/locking/lockdep.c:3168 [inline] check_prevs_add kernel/locking/lockdep.c:3287 [inline] validate_chain+0xb9b/0x2140 kernel/locking/lockdep.c:3911 __lock_acquire+0xab9/0xd20 kernel/locking/lockdep.c:5240 lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5871 down_read_killable+0x50/0x350 kernel/locking/rwsem.c:1562 mmap_read_lock_killable include/linux/mmap_lock.h:432 [inline] lock_vma_under_mmap_lock mm/mmap_lock.c:189 [inline] lock_next_vma+0x802/0xdc0 mm/mmap_lock.c:264 get_next_vma fs/proc/task_mmu.c:182 [inline] query_vma_find_by_addr fs/proc/task_mmu.c:512 [inline] query_matching_vma+0x319/0x5c0 fs/proc/task_mmu.c:544 do_procmap_query fs/proc/task_mmu.c:629 [inline] procfs_procmap_ioctl+0x3f9/0xd50 fs/proc/task_mmu.c:747 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:598 [inline] __se_sys_ioctl+0xfc/0x170 fs/ioctl.c:584 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: 0033:0x7fa51ab8e929 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:00007fa51b99b038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007fa51adb5fa0 RCX: 00007fa51ab8e929 RDX: 0000200000000180 RSI: 00000000c0686611 RDI: 0000000000000003 RBP: 00007fa51ac10b39 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007fa51adb5fa0 R15: 00007ffdecbd3a88 --- 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.