Hi, We observed an issue "BUG: unable to handle kernel paging request in __kernfs_new_node" during fuzzing. Althogh the issue was detected in a kernfs API, we report this issue to the usb gadget subsystem as we suspect that it is the most related subsystem. Unfortunately, we have not found a reproducer for the crash yet. We will inform you if we have any update on this crash. Detailed crash information is attached below. Best regards, Dae R. Jeong ----- - Kernel version: 6.2-rc7 - Crash report: BUG: unable to handle page fault for address: ffff8800302e746d #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page PGD 0 P4D 0 Oops: 0000 [#1] PREEMPT SMP CPU: 1 PID: 438 Comm: syz-executor.0 Not tainted 6.2.0-rc7-32171-g7f09e8f6ebfb #5 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.14.0-0-g155821a1990b-prebuilt.qemu.org 04/01/2014 RIP: 0010:freelist_dereference mm/slub.c:388 [inline] RIP: 0010:get_freepointer mm/slub.c:395 [inline] RIP: 0010:get_freepointer_safe mm/slub.c:422 [inline] RIP: 0010:__slab_alloc_node mm/slub.c:3347 [inline] RIP: 0010:slab_alloc_node mm/slub.c:3442 [inline] RIP: 0010:__kmem_cache_alloc_node+0x1b6/0x430 mm/slub.c:3491 Code: 48 89 df e8 6c 25 e7 ff 49 c1 ed 3a 44 3b 6d c0 0f 85 08 01 00 00 41 8b 5e 28 4c 8b 6d b8 4c 89 ef e8 0e 25 e7 ff 49 8d 3c 1c <49> 8b 1c 1c e8 41 25 e7 ff 49 8d 47 08 48 89 45 a0 49 8b 06 48 89 RSP: 0018:ffff888010c238f8 EFLAGS: 00010246 RAX: 0000000000000000 RBX: 0000000000000008 RCX: ffffc900078ee000 RDX: 0000000000000004 RSI: ffff888008441328 RDI: ffff8800302e746d RBP: ffff888010c23968 R08: ffffffff8a667a61 R09: 00000000000009d6 R10: 0000000000000010 R11: ffff888011942180 R12: ffff8800302e7465 R13: ffff888008441328 R14: ffff888008441300 R15: 00000000000bd3f1 FS: 00007f288fea9700(0000) GS:ffff88813dc00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffff8800302e746d CR3: 0000000040920000 CR4: 00000000003506e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: <TASK> __do_kmalloc_node mm/slab_common.c:967 [inline] __kmalloc_node_track_caller+0xa6/0x2a0 mm/slab_common.c:988 kstrdup mm/util.c:61 [inline] kstrdup_const+0x5a/0xa0 mm/util.c:84 __kernfs_new_node+0x4d/0x3f0 fs/kernfs/dir.c:610 kernfs_new_node fs/kernfs/dir.c:676 [inline] kernfs_create_dir_ns+0x70/0x180 fs/kernfs/dir.c:1032 sysfs_create_dir_ns+0x96/0x1a0 fs/sysfs/dir.c:59 create_dir lib/kobject.c:63 [inline] kobject_add_internal+0x2be/0x640 lib/kobject.c:223 kobject_add_varg lib/kobject.c:358 [inline] kobject_init_and_add+0xa3/0xe0 lib/kobject.c:441 bus_add_driver+0x145/0x3f0 drivers/base/bus.c:611 driver_register+0x1de/0x2a0 drivers/base/driver.c:246 usb_gadget_register_driver_owner+0x92/0x1b0 drivers/usb/gadget/udc/core.c:1560 raw_ioctl_run drivers/usb/gadget/legacy/raw_gadget.c:546 [inline] raw_ioctl+0xbb9/0x1cf0 drivers/usb/gadget/legacy/raw_gadget.c:1253 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:870 [inline] __se_sys_ioctl+0xe4/0x160 fs/ioctl.c:856 __x64_sys_ioctl+0x4b/0x60 fs/ioctl.c:856 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x4e/0xa0 arch/x86/entry/common.c:82 entry_SYSCALL_64_after_hwframe+0x63/0xcd RIP: 0033:0x478ab7 Code: 8f 38 02 00 85 c0 78 df 48 83 c4 08 48 89 d8 5b 5d c3 90 48 89 e8 48 f7 d8 48 39 c3 0f 92 c0 eb b4 66 90 b8 10 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 bc ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f288fea6b18 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 000000000000004d RCX: 0000000000478ab7 RDX: 0000000000000000 RSI: 0000000000005501 RDI: 0000000000000003 RBP: 0000000000000003 R08: 0000000000000000 R09: 000000000000000b R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000020000940 R14: 00000000004022a0 R15: 0000000020000540 </TASK> Modules linked in: CR2: ffff8800302e746d ---[ end trace 0000000000000000 ]--- RIP: 0010:freelist_dereference mm/slub.c:388 [inline] RIP: 0010:get_freepointer mm/slub.c:395 [inline] RIP: 0010:get_freepointer_safe mm/slub.c:422 [inline] RIP: 0010:__slab_alloc_node mm/slub.c:3347 [inline] RIP: 0010:slab_alloc_node mm/slub.c:3442 [inline] RIP: 0010:__kmem_cache_alloc_node+0x1b6/0x430 mm/slub.c:3491 Code: 48 89 df e8 6c 25 e7 ff 49 c1 ed 3a 44 3b 6d c0 0f 85 08 01 00 00 41 8b 5e 28 4c 8b 6d b8 4c 89 ef e8 0e 25 e7 ff 49 8d 3c 1c <49> 8b 1c 1c e8 41 25 e7 ff 49 8d 47 08 48 89 45 a0 49 8b 06 48 89 RSP: 0018:ffff888010c238f8 EFLAGS: 00010246 RAX: 0000000000000000 RBX: 0000000000000008 RCX: ffffc900078ee000 RDX: 0000000000000004 RSI: ffff888008441328 RDI: ffff8800302e746d RBP: ffff888010c23968 R08: ffffffff8a667a61 R09: 00000000000009d6 R10: 0000000000000010 R11: ffff888011942180 R12: ffff8800302e7465 R13: ffff888008441328 R14: ffff888008441300 R15: 00000000000bd3f1 FS: 00007f288fea9700(0000) GS:ffff88813dc00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffff8800302e746d CR3: 0000000040920000 CR4: 00000000003506e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 ---------------- Code disassembly (best guess): 0: 48 89 df mov %rbx,%rdi 3: e8 6c 25 e7 ff callq 0xffe72574 8: 49 c1 ed 3a shr $0x3a,%r13 c: 44 3b 6d c0 cmp -0x40(%rbp),%r13d 10: 0f 85 08 01 00 00 jne 0x11e 16: 41 8b 5e 28 mov 0x28(%r14),%ebx 1a: 4c 8b 6d b8 mov -0x48(%rbp),%r13 1e: 4c 89 ef mov %r13,%rdi 21: e8 0e 25 e7 ff callq 0xffe72534 26: 49 8d 3c 1c lea (%r12,%rbx,1),%rdi * 2a: 49 8b 1c 1c mov (%r12,%rbx,1),%rbx <-- trapping instruction 2e: e8 41 25 e7 ff callq 0xffe72574 33: 49 8d 47 08 lea 0x8(%r15),%rax 37: 48 89 45 a0 mov %rax,-0x60(%rbp) 3b: 49 8b 06 mov (%r14),%rax 3e: 48 rex.W 3f: 89 .byte 0x89
