================================================================== BUG: KASAN: use-after-free in get_disk_and_module block/genhd.c:1787 [inline] BUG: KASAN: use-after-free in exact_lock+0x38/0xc0 block/genhd.c:677 Read of size 8 at addr ffff88810962b460 by task syz.1.8065/29173 CPU: 0 PID: 29173 Comm: syz.1.8065 Tainted: G W 5.10.238-syzkaller-00282-gd76d4cd0623a #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 Call Trace: __dump_stack+0x21/0x24 lib/dump_stack.c:77 dump_stack_lvl+0x169/0x1d8 lib/dump_stack.c:118 print_address_description+0x7f/0x2c0 mm/kasan/report.c:248 __kasan_report mm/kasan/report.c:435 [inline] kasan_report+0xe2/0x130 mm/kasan/report.c:452 __asan_report_load8_noabort+0x14/0x20 mm/kasan/report_generic.c:309 get_disk_and_module block/genhd.c:1787 [inline] exact_lock+0x38/0xc0 block/genhd.c:677 kobj_lookup+0x298/0x430 drivers/base/map.c:119 get_gendisk+0xe9/0x340 block/genhd.c:1001 bdev_get_gendisk fs/block_dev.c:1110 [inline] __blkdev_get+0x1b0/0x12f0 fs/block_dev.c:1474 blkdev_get fs/block_dev.c:1653 [inline] blkdev_get_by_path+0x253/0x470 fs/block_dev.c:1690 mount_bdev+0x50/0x3a0 fs/super.c:1400 vfat_mount+0x34/0x40 fs/fat/namei_vfat.c:1057 legacy_get_tree+0xed/0x190 fs/fs_context.c:593 vfs_get_tree+0x89/0x260 fs/super.c:1572 do_new_mount+0x25a/0xa20 fs/namespace.c:2915 path_mount+0x572/0xc80 fs/namespace.c:3245 do_mount fs/namespace.c:3258 [inline] __do_sys_mount fs/namespace.c:3466 [inline] __se_sys_mount+0x318/0x380 fs/namespace.c:3443 __x64_sys_mount+0xbf/0xd0 fs/namespace.c:3443 do_syscall_64+0x31/0x40 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x61/0xcb RIP: 0033:0x7fdaf28ab929 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:00007fdaf0f14038 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5 RAX: ffffffffffffffda RBX: 00007fdaf2ad2fa0 RCX: 00007fdaf28ab929 RDX: 0000200000001200 RSI: 00002000000000c0 RDI: 00002000000001c0 RBP: 00007fdaf292db39 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007fdaf2ad2fa0 R15: 00007ffc2bd40158 Allocated by task 28832: kasan_save_stack mm/kasan/common.c:38 [inline] kasan_set_track mm/kasan/common.c:45 [inline] set_alloc_info mm/kasan/common.c:430 [inline] ____kasan_kmalloc mm/kasan/common.c:509 [inline] __kasan_kmalloc+0xda/0x110 mm/kasan/common.c:518 kasan_kmalloc include/linux/kasan.h:254 [inline] kmem_cache_alloc_trace+0x184/0x2e0 mm/slub.c:2974 kmalloc include/linux/slab.h:552 [inline] kzalloc include/linux/slab.h:664 [inline] copy_verifier_state+0x5a2/0xc20 kernel/bpf/verifier.c:913 is_state_visited kernel/bpf/verifier.c:9937 [inline] do_check+0x3546/0xdf40 kernel/bpf/verifier.c:10056 do_check_common+0x8e3/0x1160 kernel/bpf/verifier.c:12047 do_check_main kernel/bpf/verifier.c:12110 [inline] bpf_check+0x9371/0xd720 kernel/bpf/verifier.c:12665 bpf_prog_load+0xf5a/0x1420 kernel/bpf/syscall.c:2234 __do_sys_bpf kernel/bpf/syscall.c:4435 [inline] __se_sys_bpf+0x442/0x680 kernel/bpf/syscall.c:4391 __x64_sys_bpf+0x7b/0x90 kernel/bpf/syscall.c:4391 do_syscall_64+0x31/0x40 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x61/0xcb Freed by task 28832: kasan_save_stack mm/kasan/common.c:38 [inline] kasan_set_track+0x4a/0x70 mm/kasan/common.c:45 kasan_set_free_info+0x23/0x40 mm/kasan/generic.c:370 ____kasan_slab_free+0x125/0x160 mm/kasan/common.c:362 __kasan_slab_free+0x11/0x20 mm/kasan/common.c:370 kasan_slab_free include/linux/kasan.h:220 [inline] slab_free_hook mm/slub.c:1595 [inline] slab_free_freelist_hook+0xc5/0x190 mm/slub.c:1621 slab_free mm/slub.c:3203 [inline] kfree+0xc0/0x270 mm/slub.c:4191 free_func_state kernel/bpf/verifier.c:839 [inline] free_verifier_state+0xde/0x220 kernel/bpf/verifier.c:855 is_state_visited kernel/bpf/verifier.c:9886 [inline] do_check+0x1a81/0xdf40 kernel/bpf/verifier.c:10056 do_check_common+0x8e3/0x1160 kernel/bpf/verifier.c:12047 do_check_main kernel/bpf/verifier.c:12110 [inline] bpf_check+0x9371/0xd720 kernel/bpf/verifier.c:12665 bpf_prog_load+0xf5a/0x1420 kernel/bpf/syscall.c:2234 __do_sys_bpf kernel/bpf/syscall.c:4435 [inline] __se_sys_bpf+0x442/0x680 kernel/bpf/syscall.c:4391 __x64_sys_bpf+0x7b/0x90 kernel/bpf/syscall.c:4391 do_syscall_64+0x31/0x40 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x61/0xcb The buggy address belongs to the object at ffff88810962b000 which belongs to the cache kmalloc-2k of size 2048 The buggy address is located 1120 bytes inside of 2048-byte region [ffff88810962b000, ffff88810962b800) The buggy address belongs to the page: page:ffffea0004258a00 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x109628 head:ffffea0004258a00 order:3 compound_mapcount:0 compound_pincount:0 flags: 0x4000000000010200(slab|head) raw: 4000000000010200 dead000000000100 dead000000000122 ffff888100042d80 raw: 0000000000000000 0000000000080008 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 3, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 1, ts 2614217439, free_ts 0 set_page_owner include/linux/page_owner.h:35 [inline] post_alloc_hook mm/page_alloc.c:2456 [inline] prep_new_page+0x179/0x180 mm/page_alloc.c:2462 get_page_from_freelist+0x2235/0x23d0 mm/page_alloc.c:4254 __alloc_pages_nodemask+0x268/0x5f0 mm/page_alloc.c:5357 alloc_slab_page mm/slub.c:-1 [inline] allocate_slab mm/slub.c:1808 [inline] new_slab+0x84/0x3f0 mm/slub.c:1869 new_slab_objects mm/slub.c:2627 [inline] ___slab_alloc+0x2a6/0x450 mm/slub.c:2791 __slab_alloc+0x63/0xa0 mm/slub.c:2831 slab_alloc_node mm/slub.c:2913 [inline] slab_alloc mm/slub.c:2955 [inline] kmem_cache_alloc_trace+0x1b3/0x2e0 mm/slub.c:2972 kmem_cache_alloc_node_trace include/linux/slab.h:440 [inline] kmalloc_node include/linux/slab.h:570 [inline] kzalloc_node include/linux/slab.h:675 [inline] bdi_alloc+0x4e/0x110 mm/backing-dev.c:746 blk_alloc_queue+0x103/0x610 block/blk-core.c:535 blk_mq_init_queue_data block/blk-mq.c:3155 [inline] blk_mq_init_queue+0x37/0xd0 block/blk-mq.c:3174 loop_add+0x266/0x7b0 drivers/block/loop.c:2140 loop_init+0x1bf/0x1ff drivers/block/loop.c:2403 do_one_initcall+0x187/0x510 init/main.c:1197 do_initcall_level+0x16f/0x2cf init/main.c:1270 do_initcalls+0x50/0x92 init/main.c:1286 do_basic_setup+0x88/0x8f init/main.c:1306 page_owner free stack trace missing Memory state around the buggy address: ffff88810962b300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88810962b380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff88810962b400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88810962b480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88810962b500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ================================================================== general protection fault, probably for non-canonical address 0xdffffc000000000c: 0000 [#1] PREEMPT SMP KASAN KASAN: null-ptr-deref in range [0x0000000000000060-0x0000000000000067] CPU: 0 PID: 29173 Comm: syz.1.8065 Tainted: G B W 5.10.238-syzkaller-00282-gd76d4cd0623a #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 RIP: 0010:get_disk_and_module block/genhd.c:1789 [inline] RIP: 0010:exact_lock+0x4b/0xc0 block/genhd.c:677 Code: 00 4c 89 f0 48 c1 e8 03 42 80 3c 38 00 74 08 4c 89 f7 e8 78 f8 6d ff 4d 8b 36 4d 85 f6 74 35 49 83 c6 68 4c 89 f0 48 c1 e8 03 <42> 80 3c 38 00 74 08 4c 89 f7 e8 56 f8 6d ff 4d 8b 36 4d 85 f6 74 RSP: 0018:ffffc90000c878d0 EFLAGS: 00010207 RAX: 000000000000000c RBX: ffff88810962b000 RCX: 0000000000000286 RDX: ffffc90012bb6000 RSI: 000000000007ffff RDI: 0000000000080000 RBP: ffffc90000c878e8 R08: 0000000000000004 R09: 0000000000000003 R10: fffffbfff0d8e448 R11: 1ffffffff0d8e448 R12: ffff88810962b000 R13: 0000000000700003 R14: 0000000000000067 R15: dffffc0000000000 FS: 00007fdaf0f146c0(0000) GS:ffff8881f7000000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffffffffffffffe8 CR3: 000000012d774000 CR4: 00000000003506b0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: kobj_lookup+0x298/0x430 drivers/base/map.c:119 get_gendisk+0xe9/0x340 block/genhd.c:1001 bdev_get_gendisk fs/block_dev.c:1110 [inline] __blkdev_get+0x1b0/0x12f0 fs/block_dev.c:1474 blkdev_get fs/block_dev.c:1653 [inline] blkdev_get_by_path+0x253/0x470 fs/block_dev.c:1690 mount_bdev+0x50/0x3a0 fs/super.c:1400 vfat_mount+0x34/0x40 fs/fat/namei_vfat.c:1057 legacy_get_tree+0xed/0x190 fs/fs_context.c:593 vfs_get_tree+0x89/0x260 fs/super.c:1572 do_new_mount+0x25a/0xa20 fs/namespace.c:2915 path_mount+0x572/0xc80 fs/namespace.c:3245 do_mount fs/namespace.c:3258 [inline] __do_sys_mount fs/namespace.c:3466 [inline] __se_sys_mount+0x318/0x380 fs/namespace.c:3443 __x64_sys_mount+0xbf/0xd0 fs/namespace.c:3443 do_syscall_64+0x31/0x40 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x61/0xcb RIP: 0033:0x7fdaf28ab929 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:00007fdaf0f14038 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5 RAX: ffffffffffffffda RBX: 00007fdaf2ad2fa0 RCX: 00007fdaf28ab929 RDX: 0000200000001200 RSI: 00002000000000c0 RDI: 00002000000001c0 RBP: 00007fdaf292db39 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007fdaf2ad2fa0 R15: 00007ffc2bd40158 Modules linked in: ---[ end trace bc3f0152c13b71f3 ]--- RIP: 0010:get_disk_and_module block/genhd.c:1789 [inline] RIP: 0010:exact_lock+0x4b/0xc0 block/genhd.c:677 Code: 00 4c 89 f0 48 c1 e8 03 42 80 3c 38 00 74 08 4c 89 f7 e8 78 f8 6d ff 4d 8b 36 4d 85 f6 74 35 49 83 c6 68 4c 89 f0 48 c1 e8 03 <42> 80 3c 38 00 74 08 4c 89 f7 e8 56 f8 6d ff 4d 8b 36 4d 85 f6 74 RSP: 0018:ffffc90000c878d0 EFLAGS: 00010207 RAX: 000000000000000c RBX: ffff88810962b000 RCX: 0000000000000286 RDX: ffffc90012bb6000 RSI: 000000000007ffff RDI: 0000000000080000 RBP: ffffc90000c878e8 R08: 0000000000000004 R09: 0000000000000003 R10: fffffbfff0d8e448 R11: 1ffffffff0d8e448 R12: ffff88810962b000 R13: 0000000000700003 R14: 0000000000000067 R15: dffffc0000000000 FS: 00007fdaf0f146c0(0000) GS:ffff8881f7100000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffffffffffffffe8 CR3: 000000012d774000 CR4: 00000000003506a0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 ---------------- Code disassembly (best guess): 0: 00 4c 89 f0 add %cl,-0x10(%rcx,%rcx,4) 4: 48 c1 e8 03 shr $0x3,%rax 8: 42 80 3c 38 00 cmpb $0x0,(%rax,%r15,1) d: 74 08 je 0x17 f: 4c 89 f7 mov %r14,%rdi 12: e8 78 f8 6d ff call 0xff6df88f 17: 4d 8b 36 mov (%r14),%r14 1a: 4d 85 f6 test %r14,%r14 1d: 74 35 je 0x54 1f: 49 83 c6 68 add $0x68,%r14 23: 4c 89 f0 mov %r14,%rax 26: 48 c1 e8 03 shr $0x3,%rax * 2a: 42 80 3c 38 00 cmpb $0x0,(%rax,%r15,1) <-- trapping instruction 2f: 74 08 je 0x39 31: 4c 89 f7 mov %r14,%rdi 34: e8 56 f8 6d ff call 0xff6df88f 39: 4d 8b 36 mov (%r14),%r14 3c: 4d 85 f6 test %r14,%r14 3f: 74 .byte 0x74