================================================================== BUG: KASAN: use-after-free in do_shrink_slab+0xb15/0xbd0 mm/vmscan.c:774 Read of size 8 at addr ffff8880257925b8 by task udevd/3722 CPU: 1 PID: 3722 Comm: udevd Not tainted 6.0.0-syzkaller-09039-ga6afa4199d3d #0 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.14.0-2 04/01/2014 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106 print_address_description mm/kasan/report.c:317 [inline] print_report.cold+0x2ba/0x719 mm/kasan/report.c:433 kasan_report+0xb1/0x1e0 mm/kasan/report.c:495 do_shrink_slab+0xb15/0xbd0 mm/vmscan.c:774 shrink_slab+0x17c/0x6f0 mm/vmscan.c:991 shrink_node_memcgs mm/vmscan.c:3182 [inline] shrink_node+0x8c9/0x1e80 mm/vmscan.c:3304 shrink_zones mm/vmscan.c:3542 [inline] do_try_to_free_pages+0x3b4/0x17a0 mm/vmscan.c:3601 try_to_free_pages+0x2a7/0x840 mm/vmscan.c:3836 __perform_reclaim mm/page_alloc.c:4750 [inline] __alloc_pages_direct_reclaim mm/page_alloc.c:4772 [inline] __alloc_pages_slowpath.constprop.0+0x88a/0x2300 mm/page_alloc.c:5177 __alloc_pages+0x43d/0x510 mm/page_alloc.c:5562 __folio_alloc+0x12/0x40 mm/page_alloc.c:5580 vma_alloc_folio+0xf9/0x780 mm/mempolicy.c:2231 alloc_page_vma include/linux/gfp.h:290 [inline] wp_page_copy+0x1f1/0x1b10 mm/memory.c:3112 do_wp_page+0x52c/0x1910 mm/memory.c:3479 handle_pte_fault mm/memory.c:4935 [inline] __handle_mm_fault+0x1813/0x39b0 mm/memory.c:5059 handle_mm_fault+0x1c8/0x780 mm/memory.c:5157 do_user_addr_fault+0x475/0x1210 arch/x86/mm/fault.c:1407 handle_page_fault arch/x86/mm/fault.c:1498 [inline] exc_page_fault+0x94/0x170 arch/x86/mm/fault.c:1554 asm_exc_page_fault+0x22/0x30 arch/x86/include/asm/idtentry.h:570 RIP: 0010:__put_user_nocheck_4+0x3/0x11 Code: 00 00 48 39 d9 73 54 0f 1f 00 66 89 01 31 c9 0f 1f 00 c3 0f 1f 44 00 00 48 bb fd ef ff ff ff 7f 00 00 48 39 d9 73 34 0f 1f 00 <89> 01 31 c9 0f 1f 00 c3 66 0f 1f 44 00 00 48 bb f9 ef ff ff ff 7f RSP: 0000:ffffc9000398ff38 EFLAGS: 00010293 RAX: 0000000000000e8a RBX: 00007fffffffeffd RCX: 00007fe401fbdb10 RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff8de0a450 RBP: 00007fe401fbdb10 R08: 0000000000000000 R09: ffffffff8de0a457 R10: 0000000000000000 R11: 0000000000000001 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 schedule_tail+0xaa/0xd0 kernel/sched/core.c:5123 ret_from_fork+0x8/0x30 arch/x86/entry/entry_64.S:291 Allocated by task 3710: kasan_save_stack+0x1e/0x40 mm/kasan/common.c:38 kasan_set_track mm/kasan/common.c:45 [inline] set_alloc_info mm/kasan/common.c:437 [inline] ____kasan_kmalloc mm/kasan/common.c:516 [inline] ____kasan_kmalloc mm/kasan/common.c:475 [inline] __kasan_kmalloc+0xa9/0xd0 mm/kasan/common.c:525 kmalloc include/linux/slab.h:605 [inline] kzalloc include/linux/slab.h:733 [inline] ops_init+0xfb/0x470 net/core/net_namespace.c:124 setup_net+0x5d1/0xc50 net/core/net_namespace.c:325 copy_net_ns+0x318/0x760 net/core/net_namespace.c:471 create_new_namespaces+0x3f6/0xb20 kernel/nsproxy.c:110 unshare_nsproxy_namespaces+0xc1/0x1f0 kernel/nsproxy.c:226 ksys_unshare+0x445/0x920 kernel/fork.c:3181 __do_sys_unshare kernel/fork.c:3252 [inline] __se_sys_unshare kernel/fork.c:3250 [inline] __ia32_sys_unshare+0x2c/0x40 kernel/fork.c:3250 do_syscall_32_irqs_on arch/x86/entry/common.c:112 [inline] __do_fast_syscall_32+0x65/0xf0 arch/x86/entry/common.c:178 do_fast_syscall_32+0x2f/0x70 arch/x86/entry/common.c:203 entry_SYSENTER_compat_after_hwframe+0x70/0x82 Freed by task 3710: kasan_save_stack+0x1e/0x40 mm/kasan/common.c:38 kasan_set_track+0x21/0x30 mm/kasan/common.c:45 kasan_set_free_info+0x20/0x30 mm/kasan/generic.c:370 ____kasan_slab_free mm/kasan/common.c:367 [inline] ____kasan_slab_free+0x166/0x1c0 mm/kasan/common.c:329 kasan_slab_free include/linux/kasan.h:200 [inline] slab_free_hook mm/slub.c:1759 [inline] slab_free_freelist_hook+0x8b/0x1c0 mm/slub.c:1785 slab_free mm/slub.c:3539 [inline] kfree+0xe2/0x580 mm/slub.c:4567 ops_init+0xcd/0x470 net/core/net_namespace.c:139 setup_net+0x5d1/0xc50 net/core/net_namespace.c:325 copy_net_ns+0x318/0x760 net/core/net_namespace.c:471 create_new_namespaces+0x3f6/0xb20 kernel/nsproxy.c:110 unshare_nsproxy_namespaces+0xc1/0x1f0 kernel/nsproxy.c:226 ksys_unshare+0x445/0x920 kernel/fork.c:3181 __do_sys_unshare kernel/fork.c:3252 [inline] __se_sys_unshare kernel/fork.c:3250 [inline] __ia32_sys_unshare+0x2c/0x40 kernel/fork.c:3250 do_syscall_32_irqs_on arch/x86/entry/common.c:112 [inline] __do_fast_syscall_32+0x65/0xf0 arch/x86/entry/common.c:178 do_fast_syscall_32+0x2f/0x70 arch/x86/entry/common.c:203 entry_SYSENTER_compat_after_hwframe+0x70/0x82 The buggy address belongs to the object at ffff888025792000 which belongs to the cache kmalloc-2k of size 2048 The buggy address is located 1464 bytes inside of 2048-byte region [ffff888025792000, ffff888025792800) The buggy address belongs to the physical page: page:ffffea000095e400 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x25790 head:ffffea000095e400 order:3 compound_mapcount:0 compound_pincount:0 flags: 0xfff00000010200(slab|head|node=0|zone=1|lastcpupid=0x7ff) raw: 00fff00000010200 0000000000000000 dead000000000122 ffff888011842f00 raw: 0000000000000000 0000000080080008 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 3710, tgid 3710 (syz-executor.0), ts 208927168821, free_ts 207199161091 prep_new_page mm/page_alloc.c:2532 [inline] get_page_from_freelist+0x109b/0x2ce0 mm/page_alloc.c:4283 __alloc_pages_slowpath.constprop.0+0x34d/0x2300 mm/page_alloc.c:5084 __alloc_pages+0x43d/0x510 mm/page_alloc.c:5562 alloc_pages+0x1a6/0x270 mm/mempolicy.c:2270 alloc_slab_page mm/slub.c:1829 [inline] allocate_slab+0x27e/0x3d0 mm/slub.c:1974 new_slab mm/slub.c:2034 [inline] ___slab_alloc+0x84f/0xe80 mm/slub.c:3036 __slab_alloc.constprop.0+0x4d/0xa0 mm/slub.c:3123 slab_alloc_node mm/slub.c:3214 [inline] slab_alloc mm/slub.c:3256 [inline] __kmalloc+0x32b/0x340 mm/slub.c:4425 kmalloc_array include/linux/slab.h:640 [inline] kcalloc include/linux/slab.h:671 [inline] cache_create_net+0xa3/0x220 net/sunrpc/cache.c:1749 ip_map_cache_create+0x143/0x360 net/sunrpc/svcauth_unix.c:957 sunrpc_init_net+0x139/0x3c0 net/sunrpc/sunrpc_syms.c:42 ops_init+0xaf/0x470 net/core/net_namespace.c:134 setup_net+0x5d1/0xc50 net/core/net_namespace.c:325 copy_net_ns+0x318/0x760 net/core/net_namespace.c:471 create_new_namespaces+0x3f6/0xb20 kernel/nsproxy.c:110 unshare_nsproxy_namespaces+0xc1/0x1f0 kernel/nsproxy.c:226 page last free stack trace: reset_page_owner include/linux/page_owner.h:24 [inline] free_pages_prepare mm/page_alloc.c:1449 [inline] free_pcp_prepare+0x5e4/0xd20 mm/page_alloc.c:1499 free_unref_page_prepare mm/page_alloc.c:3380 [inline] free_unref_page_list+0x16f/0xb90 mm/page_alloc.c:3522 shrink_page_list+0x2ba9/0x3810 mm/vmscan.c:2040 shrink_inactive_list mm/vmscan.c:2447 [inline] shrink_list mm/vmscan.c:2674 [inline] shrink_lruvec+0xce4/0x2650 mm/vmscan.c:2991 shrink_node_memcgs mm/vmscan.c:3180 [inline] shrink_node+0x85e/0x1e80 mm/vmscan.c:3304 kswapd_shrink_node mm/vmscan.c:4086 [inline] balance_pgdat+0x8ef/0x1580 mm/vmscan.c:4277 kswapd+0x79b/0xf80 mm/vmscan.c:4537 kthread+0x2e4/0x3a0 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306 Memory state around the buggy address: ffff888025792480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888025792500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff888025792580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888025792600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888025792680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ================================================================== ---------------- Code disassembly (best guess): 0: 00 00 add %al,(%rax) 2: 48 39 d9 cmp %rbx,%rcx 5: 73 54 jae 0x5b 7: 0f 1f 00 nopl (%rax) a: 66 89 01 mov %ax,(%rcx) d: 31 c9 xor %ecx,%ecx f: 0f 1f 00 nopl (%rax) 12: c3 retq 13: 0f 1f 44 00 00 nopl 0x0(%rax,%rax,1) 18: 48 bb fd ef ff ff ff movabs $0x7fffffffeffd,%rbx 1f: 7f 00 00 22: 48 39 d9 cmp %rbx,%rcx 25: 73 34 jae 0x5b 27: 0f 1f 00 nopl (%rax) * 2a: 89 01 mov %eax,(%rcx) <-- trapping instruction 2c: 31 c9 xor %ecx,%ecx 2e: 0f 1f 00 nopl (%rax) 31: c3 retq 32: 66 0f 1f 44 00 00 nopw 0x0(%rax,%rax,1) 38: 48 rex.W 39: bb f9 ef ff ff mov $0xffffeff9,%ebx 3e: ff (bad) 3f: 7f .byte 0x7f