syzbot has found a reproducer for the following issue on: HEAD commit: e32cde8d2bd7 Merge tag 'sched_ext-for-6.12-rc1-fixes-1' of.. git tree: upstream console+strace: https://syzkaller.appspot.com/x/log.txt?x=14ed139f980000 kernel config: https://syzkaller.appspot.com/x/.config?x=286b31f2cf1c36b5 dashboard link: https://syzkaller.appspot.com/bug?extid=a6456f6334aa19425886 compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40 syz repro: https://syzkaller.appspot.com/x/repro.syz?x=154e8927980000 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1244bdd0580000 Downloadable assets: disk image: https://storage.googleapis.com/syzbot-assets/f7f2dc1bf47b/disk-e32cde8d.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/063e4eafb554/vmlinux-e32cde8d.xz kernel image: https://storage.googleapis.com/syzbot-assets/7ce38bae7b74/bzImage-e32cde8d.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+a6456f6334aa19425886@xxxxxxxxxxxxxxxxxxxxxxxxx mmap: syz-executor813 (5232) uses deprecated remap_file_pages() syscall. See Documentation/mm/remap_file_pages.rst. ====================================================== WARNING: possible circular locking dependency detected 6.12.0-rc1-syzkaller-00031-ge32cde8d2bd7 #0 Not tainted ------------------------------------------------------ syz-executor813/5232 is trying to acquire lock: ffff88807bfa0198 (&mm->mmap_lock){++++}-{3:3}, at: mmap_write_lock_killable include/linux/mmap_lock.h:122 [inline] ffff88807bfa0198 (&mm->mmap_lock){++++}-{3:3}, at: upgrade_mmap_lock_carefully+0xb6/0x160 mm/memory.c:6132 but task is already holding lock: ffff888022786b48 (&sb->s_type->i_mutex_key#12){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:815 [inline] ffff888022786b48 (&sb->s_type->i_mutex_key#12){+.+.}-{3:3}, at: shmem_file_write_iter+0x80/0x120 mm/shmem.c:3211 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (&sb->s_type->i_mutex_key#12){+.+.}-{3:3}: lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5825 down_write+0x99/0x220 kernel/locking/rwsem.c:1577 inode_lock include/linux/fs.h:815 [inline] process_measurement+0x439/0x1fb0 security/integrity/ima/ima_main.c:250 ima_file_mmap+0x13d/0x2b0 security/integrity/ima/ima_main.c:455 security_mmap_file+0x7e7/0xa40 security/security.c:2977 __do_sys_remap_file_pages mm/mmap.c:1692 [inline] __se_sys_remap_file_pages+0x6e6/0xa50 mm/mmap.c:1624 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #0 (&mm->mmap_lock){++++}-{3:3}: check_prev_add kernel/locking/lockdep.c:3161 [inline] check_prevs_add kernel/locking/lockdep.c:3280 [inline] validate_chain+0x18ef/0x5920 kernel/locking/lockdep.c:3904 __lock_acquire+0x1384/0x2050 kernel/locking/lockdep.c:5202 lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5825 down_write_killable+0xab/0x260 kernel/locking/rwsem.c:1588 mmap_write_lock_killable include/linux/mmap_lock.h:122 [inline] upgrade_mmap_lock_carefully+0xb6/0x160 mm/memory.c:6132 lock_mm_and_find_vma+0x107/0x2f0 mm/memory.c:6185 do_user_addr_fault arch/x86/mm/fault.c:1361 [inline] handle_page_fault arch/x86/mm/fault.c:1481 [inline] exc_page_fault+0x1bf/0x8c0 arch/x86/mm/fault.c:1539 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623 fault_in_readable+0x165/0x2b0 fault_in_iov_iter_readable+0x229/0x280 lib/iov_iter.c:94 generic_perform_write+0x259/0x6d0 mm/filemap.c:4044 shmem_file_write_iter+0xf9/0x120 mm/shmem.c:3221 new_sync_write fs/read_write.c:590 [inline] vfs_write+0xa6d/0xc90 fs/read_write.c:683 ksys_write+0x183/0x2b0 fs/read_write.c:736 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f other info that might help us debug this: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&sb->s_type->i_mutex_key#12); lock(&mm->mmap_lock); lock(&sb->s_type->i_mutex_key#12); lock(&mm->mmap_lock); *** DEADLOCK *** 2 locks held by syz-executor813/5232: #0: ffff88807b202420 (sb_writers#5){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2931 [inline] #0: ffff88807b202420 (sb_writers#5){.+.+}-{0:0}, at: vfs_write+0x224/0xc90 fs/read_write.c:679 #1: ffff888022786b48 (&sb->s_type->i_mutex_key#12){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:815 [inline] #1: ffff888022786b48 (&sb->s_type->i_mutex_key#12){+.+.}-{3:3}, at: shmem_file_write_iter+0x80/0x120 mm/shmem.c:3211 stack backtrace: CPU: 0 UID: 0 PID: 5232 Comm: syz-executor813 Not tainted 6.12.0-rc1-syzkaller-00031-ge32cde8d2bd7 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024 Call Trace: <TASK> __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120 print_circular_bug+0x13a/0x1b0 kernel/locking/lockdep.c:2074 check_noncircular+0x36a/0x4a0 kernel/locking/lockdep.c:2206 check_prev_add kernel/locking/lockdep.c:3161 [inline] check_prevs_add kernel/locking/lockdep.c:3280 [inline] validate_chain+0x18ef/0x5920 kernel/locking/lockdep.c:3904 __lock_acquire+0x1384/0x2050 kernel/locking/lockdep.c:5202 lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5825 down_write_killable+0xab/0x260 kernel/locking/rwsem.c:1588 mmap_write_lock_killable include/linux/mmap_lock.h:122 [inline] upgrade_mmap_lock_carefully+0xb6/0x160 mm/memory.c:6132 lock_mm_and_find_vma+0x107/0x2f0 mm/memory.c:6185 do_user_addr_fault arch/x86/mm/fault.c:1361 [inline] handle_page_fault arch/x86/mm/fault.c:1481 [inline] exc_page_fault+0x1bf/0x8c0 arch/x86/mm/fault.c:1539 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623 RIP: 0010:fault_in_readable+0x165/0x2b0 mm/gup.c:2235 Code: b3 ff 4c 8d b3 ff 0f 00 00 48 89 d8 4d 01 e6 49 81 e6 00 f0 ff ff 49 39 c6 72 6b e8 65 ca b3 ff 4c 39 f3 74 6e 4c 89 64 24 10 <44> 8a 23 43 0f b6 04 2f 84 c0 75 18 44 88 64 24 40 48 81 c3 00 10 RSP: 0018:ffffc90003c3fa40 EFLAGS: 00050287 RAX: ffffffff81e1114b RBX: 0000000020001000 RCX: ffff88801cf78000 RDX: 0000000000000000 RSI: 0000000000000100 RDI: 0000000000000000 RBP: ffffc90003c3faf8 R08: ffffffff81e110e8 R09: ffffffff84b94759 R10: 0000000000000002 R11: ffff88801cf78000 R12: 000000000000fecc R13: dffffc0000000000 R14: 0000000020010000 R15: 1ffff92000787f50 fault_in_iov_iter_readable+0x229/0x280 lib/iov_iter.c:94 generic_perform_write+0x259/0x6d0 mm/filemap.c:4044 shmem_file_write_iter+0xf9/0x120 mm/shmem.c:3221 new_sync_write fs/read_write.c:590 [inline] vfs_write+0xa6d/0xc90 fs/read_write.c:683 ksys_write+0x183/0x2b0 fs/read_write.c:736 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f355e2f2a19 Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 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 b8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007ffdd6291a88 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00007f355e33c11f RCX: 00007f355e2f2a19 RDX: 000000000000fecc RSI: 0000000020000100 RDI: 0000000000000003 RBP: 00007f355e33c0fd R08: 0000000000000000 R09: 0000000000000000 R10: 0000000020005000 R11: 0000000000000246 R12: 00007f355e34113c R13: 00007f355e33c082 R14: 0000000000000001 R15: 0000000000000001 </TASK> ---------------- Code disassembly (best guess): 0: b3 ff mov $0xff,%bl 2: 4c 8d b3 ff 0f 00 00 lea 0xfff(%rbx),%r14 9: 48 89 d8 mov %rbx,%rax c: 4d 01 e6 add %r12,%r14 f: 49 81 e6 00 f0 ff ff and $0xfffffffffffff000,%r14 16: 49 39 c6 cmp %rax,%r14 19: 72 6b jb 0x86 1b: e8 65 ca b3 ff call 0xffb3ca85 20: 4c 39 f3 cmp %r14,%rbx 23: 74 6e je 0x93 25: 4c 89 64 24 10 mov %r12,0x10(%rsp) * 2a: 44 8a 23 mov (%rbx),%r12b <-- trapping instruction 2d: 43 0f b6 04 2f movzbl (%r15,%r13,1),%eax 32: 84 c0 test %al,%al 34: 75 18 jne 0x4e 36: 44 88 64 24 40 mov %r12b,0x40(%rsp) 3b: 48 rex.W 3c: 81 .byte 0x81 3d: c3 ret 3e: 00 10 add %dl,(%rax) --- 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.
