random: sshd: uninitialized urandom read (32 bytes read) random: sshd: uninitialized urandom read (32 bytes read) random: sshd: uninitialized urandom read (32 bytes read) ====================================================== WARNING: possible circular locking dependency detected 4.19.0-rc1+ #120 Not tainted ------------------------------------------------------ syz-executor964/4654 is trying to acquire lock: 00000000f13df4c6 (&rp->fetch_lock){+.+.}, at: mon_bin_vma_fault+0xdc/0x4a0 drivers/usb/mon/mon_bin.c:1237 but task is already holding lock: 000000003b4b7c07 (&mm->mmap_sem){++++}, at: __mm_populate+0x31a/0x4d0 mm/gup.c:1250 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (&mm->mmap_sem){++++}: __might_fault+0x155/0x1e0 mm/memory.c:4578 _copy_to_user+0x30/0x110 lib/usercopy.c:25 copy_to_user include/linux/uaccess.h:155 [inline] mon_bin_read+0x334/0x650 drivers/usb/mon/mon_bin.c:825 __vfs_read+0x117/0x9b0 fs/read_write.c:416 vfs_read+0x17f/0x3c0 fs/read_write.c:452 ksys_pread64+0x181/0x1b0 fs/read_write.c:626 __do_compat_sys_x86_pread arch/x86/ia32/sys_ia32.c:177 [inline] __se_compat_sys_x86_pread arch/x86/ia32/sys_ia32.c:174 [inline] __ia32_compat_sys_x86_pread+0xc4/0x130 arch/x86/ia32/sys_ia32.c:174 do_syscall_32_irqs_on arch/x86/entry/common.c:326 [inline] do_fast_syscall_32+0x34d/0xfb2 arch/x86/entry/common.c:397 entry_SYSENTER_compat+0x70/0x7f arch/x86/entry/entry_64_compat.S:139 -> #0 (&rp->fetch_lock){+.+.}: lock_acquire+0x1e4/0x4f0 kernel/locking/lockdep.c:3901 __mutex_lock_common kernel/locking/mutex.c:925 [inline] __mutex_lock+0x171/0x1700 kernel/locking/mutex.c:1073 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:1088 mon_bin_vma_fault+0xdc/0x4a0 drivers/usb/mon/mon_bin.c:1237 __do_fault+0xee/0x450 mm/memory.c:3240 do_read_fault mm/memory.c:3652 [inline] do_fault mm/memory.c:3752 [inline] handle_pte_fault mm/memory.c:3983 [inline] __handle_mm_fault+0x2b4a/0x4350 mm/memory.c:4107 handle_mm_fault+0x53e/0xc80 mm/memory.c:4144 faultin_page mm/gup.c:518 [inline] __get_user_pages+0x823/0x1b50 mm/gup.c:718 populate_vma_page_range+0x2db/0x3d0 mm/gup.c:1222 __mm_populate+0x286/0x4d0 mm/gup.c:1270 mm_populate include/linux/mm.h:2307 [inline] vm_mmap_pgoff+0x27f/0x2c0 mm/util.c:362 ksys_mmap_pgoff+0x4da/0x660 mm/mmap.c:1585 __do_sys_mmap_pgoff mm/mmap.c:1596 [inline] __se_sys_mmap_pgoff mm/mmap.c:1592 [inline] __ia32_sys_mmap_pgoff+0xdd/0x1a0 mm/mmap.c:1592 do_syscall_32_irqs_on arch/x86/entry/common.c:326 [inline] do_fast_syscall_32+0x34d/0xfb2 arch/x86/entry/common.c:397 entry_SYSENTER_compat+0x70/0x7f arch/x86/entry/entry_64_compat.S:139 other info that might help us debug this: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&mm->mmap_sem); lock(&rp->fetch_lock); lock(&mm->mmap_sem); lock(&rp->fetch_lock); *** DEADLOCK *** 1 lock held by syz-executor964/4654: #0: 000000003b4b7c07 (&mm->mmap_sem){++++}, at: __mm_populate+0x31a/0x4d0 mm/gup.c:1250 stack backtrace: CPU: 0 PID: 4654 Comm: syz-executor964 Not tainted 4.19.0-rc1+ #120 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x1c9/0x2b4 lib/dump_stack.c:113 print_circular_bug.isra.34.cold.55+0x1bd/0x27d kernel/locking/lockdep.c:1222 check_prev_add kernel/locking/lockdep.c:1862 [inline] check_prevs_add kernel/locking/lockdep.c:1975 [inline] validate_chain kernel/locking/lockdep.c:2416 [inline] __lock_acquire+0x3449/0x5020 kernel/locking/lockdep.c:3412 lock_acquire+0x1e4/0x4f0 kernel/locking/lockdep.c:3901 __mutex_lock_common kernel/locking/mutex.c:925 [inline] __mutex_lock+0x171/0x1700 kernel/locking/mutex.c:1073 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:1088 mon_bin_vma_fault+0xdc/0x4a0 drivers/usb/mon/mon_bin.c:1237 __do_fault+0xee/0x450 mm/memory.c:3240 do_read_fault mm/memory.c:3652 [inline] do_fault mm/memory.c:3752 [inline] handle_pte_fault mm/memory.c:3983 [inline] __handle_mm_fault+0x2b4a/0x4350 mm/memory.c:4107 handle_mm_fault+0x53e/0xc80 mm/memory.c:4144 faultin_page mm/gup.c:518 [inline] __get_user_pages+0x823/0x1b50 mm/gup.c:718 populate_vma_page_range+0x2db/0x3d0 mm/gup.c:1222 __mm_populate+0x286/0x4d0 mm/gup.c:1270 mm_populate include/linux/mm.h:2307 [inline] vm_mmap_pgoff+0x27f/0x2c0 mm/util.c:362 ksys_mmap_pgoff+0x4da/0x660 mm/mmap.c:1585 __do_sys_mmap_pgoff mm/mmap.c:1596 [inline] __se_sys_mmap_pgoff mm/mmap.c:1592 [inline] __ia32_sys_mmap_pgoff+0xdd/0x1a0 mm/mmap.c:1592 do_syscall_32_irqs_on arch/x86/entry/common.c:326 [inline] do_fast_syscall_32+0x34d/0xfb2 arch/x86/entry/common.c:397 entry_SYSENTER_compat+0x70/0x7f arch/x86/entry/entry_64_compat.S:139 RIP: 0023:0xf7f14ca9 Code: 55 08 8b 88 64 cd ff ff 8b 98 68 cd ff ff 89 c8 85 d2 74 02 89 0a 5b 5d c3 8b 04 24 c3 8b 1c 24 c3 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 9