================================================================== BUG: KASAN: use-after-free in do_shrink_slab+0xbe6/0xce0 mm/vmscan.c:785 Read of size 8 at addr ffff88801a73f5b8 by task syz-executor.1/7004 CPU: 0 PID: 7004 Comm: syz-executor.1 Not tainted 6.0.0-syzkaller-12255-g2df76606db9d #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:284 [inline] print_report+0x15e/0x461 mm/kasan/report.c:395 kasan_report+0xbb/0x1f0 mm/kasan/report.c:495 do_shrink_slab+0xbe6/0xce0 mm/vmscan.c:785 shrink_slab+0x175/0x660 mm/vmscan.c:1002 shrink_node_memcgs mm/vmscan.c:6076 [inline] shrink_node+0x93d/0x1f30 mm/vmscan.c:6105 shrink_zones mm/vmscan.c:6343 [inline] do_try_to_free_pages+0x3b4/0x17a0 mm/vmscan.c:6405 try_to_free_pages+0x2e1/0x960 mm/vmscan.c:6640 __perform_reclaim mm/page_alloc.c:4754 [inline] __alloc_pages_direct_reclaim mm/page_alloc.c:4776 [inline] __alloc_pages_slowpath.constprop.0+0x8b6/0x23d0 mm/page_alloc.c:5182 __alloc_pages+0x4a6/0x5a0 mm/page_alloc.c:5567 alloc_pages+0x1a6/0x270 mm/mempolicy.c:2280 folio_alloc+0x1c/0x70 mm/mempolicy.c:2290 filemap_alloc_folio+0x306/0x3a0 mm/filemap.c:971 page_cache_ra_unbounded+0x1aa/0x5e0 mm/readahead.c:248 do_page_cache_ra mm/readahead.c:300 [inline] page_cache_ra_order+0x6e8/0xa00 mm/readahead.c:560 ondemand_readahead+0x6b3/0x1000 mm/readahead.c:682 page_cache_async_ra mm/readahead.c:731 [inline] page_cache_async_ra+0x113/0x140 mm/readahead.c:713 do_async_mmap_readahead mm/filemap.c:3071 [inline] filemap_fault+0x9a2/0x2400 mm/filemap.c:3125 __do_fault+0x107/0x600 mm/memory.c:4203 do_shared_fault mm/memory.c:4609 [inline] do_fault mm/memory.c:4687 [inline] handle_pte_fault mm/memory.c:4955 [inline] __handle_mm_fault+0x2200/0x3a40 mm/memory.c:5097 handle_mm_fault+0x1c8/0x780 mm/memory.c:5218 do_user_addr_fault+0x475/0x1210 arch/x86/mm/fault.c:1428 handle_page_fault arch/x86/mm/fault.c:1519 [inline] exc_page_fault+0x94/0x170 arch/x86/mm/fault.c:1575 asm_exc_page_fault+0x22/0x30 arch/x86/include/asm/idtentry.h:570 RIP: 0010:copy_user_enhanced_fast_string+0xa/0x40 arch/x86/lib/copy_user_64.S:166 Code: ff c9 75 f2 89 d1 c1 e9 03 83 e2 07 f3 48 a5 89 d1 f3 a4 31 c0 0f 1f 00 c3 8d 0c ca 89 ca eb 20 0f 1f 00 83 fa 40 72 38 89 d1 a4 31 c0 0f 1f 00 c3 89 ca eb 0a 66 2e 0f 1f 84 00 00 00 00 00 RSP: 0018:ffffc9000390f780 EFLAGS: 00010206 RAX: 0000000000000001 RBX: 0000000000001000 RCX: 0000000000001000 RDX: 0000000000001000 RSI: ffff88804c244000 RDI: 0000000020041080 RBP: 00007fffffffe000 R08: 0000000000000000 R09: ffff88804c244fff R10: ffffed10098489ff R11: 0000000000000000 R12: 0000000020041080 R13: ffff88804c244000 R14: ffff88804c244000 R15: 0000000000000000 copy_user_generic arch/x86/include/asm/uaccess_64.h:37 [inline] raw_copy_to_user arch/x86/include/asm/uaccess_64.h:58 [inline] copyout lib/iov_iter.c:170 [inline] copyout+0xf6/0x120 lib/iov_iter.c:164 _copy_to_iter+0x531/0x1140 lib/iov_iter.c:527 copy_page_to_iter+0xdc/0xa20 lib/iov_iter.c:725 copy_folio_to_iter include/linux/uio.h:169 [inline] filemap_read+0x635/0xc00 mm/filemap.c:2726 generic_file_read_iter+0x3b0/0x5a0 mm/filemap.c:2821 ext4_file_read_iter+0x1d5/0x690 fs/ext4/file.c:147 call_read_iter include/linux/fs.h:2185 [inline] do_iter_readv_writev+0x2e0/0x3b0 fs/read_write.c:733 do_iter_read+0x2f2/0x750 fs/read_write.c:796 vfs_readv+0xe5/0x150 fs/read_write.c:916 do_preadv fs/read_write.c:1008 [inline] __do_sys_preadv fs/read_write.c:1058 [inline] __se_sys_preadv fs/read_write.c:1053 [inline] __x64_sys_preadv+0x22b/0x310 fs/read_write.c:1053 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd RIP: 0033:0x7f363ba8b5a9 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 b8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f363cb9d168 EFLAGS: 00000246 ORIG_RAX: 0000000000000127 RAX: ffffffffffffffda RBX: 00007f363bbabf80 RCX: 00007f363ba8b5a9 RDX: 0000000000000001 RSI: 00000000200015c0 RDI: 0000000000000006 RBP: 00007f363bae6580 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ffd007ac62f R14: 00007f363cb9d300 R15: 0000000000022000 Allocated by task 7007: kasan_save_stack+0x1e/0x40 mm/kasan/common.c:45 kasan_set_track+0x21/0x30 mm/kasan/common.c:52 ____kasan_kmalloc mm/kasan/common.c:371 [inline] ____kasan_kmalloc mm/kasan/common.c:330 [inline] __kasan_kmalloc+0x9f/0xb0 mm/kasan/common.c:380 kasan_kmalloc include/linux/kasan.h:211 [inline] __do_kmalloc_node mm/slab_common.c:955 [inline] __kmalloc+0x54/0xc0 mm/slab_common.c:968 kmalloc include/linux/slab.h:581 [inline] kzalloc include/linux/slab.h:712 [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:3188 __do_sys_unshare kernel/fork.c:3259 [inline] __se_sys_unshare kernel/fork.c:3257 [inline] __x64_sys_unshare+0x2d/0x40 kernel/fork.c:3257 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd Freed by task 7007: kasan_save_stack+0x1e/0x40 mm/kasan/common.c:45 kasan_set_track+0x21/0x30 mm/kasan/common.c:52 kasan_save_free_info+0x27/0x40 mm/kasan/generic.c:511 ____kasan_slab_free mm/kasan/common.c:236 [inline] ____kasan_slab_free+0x13b/0x1a0 mm/kasan/common.c:200 kasan_slab_free include/linux/kasan.h:177 [inline] __cache_free mm/slab.c:3389 [inline] __do_kmem_cache_free mm/slab.c:3585 [inline] __kmem_cache_free+0xc9/0x3a0 mm/slab.c:3592 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:3188 __do_sys_unshare kernel/fork.c:3259 [inline] __se_sys_unshare kernel/fork.c:3257 [inline] __x64_sys_unshare+0x2d/0x40 kernel/fork.c:3257 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd The buggy address belongs to the object at ffff88801a73f000 which belongs to the cache kmalloc-2k of size 2048 The buggy address is located 1464 bytes inside of 2048-byte region [ffff88801a73f000, ffff88801a73f800) The buggy address belongs to the physical page: page:ffffea000069cfc0 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x1a73f flags: 0xfff00000000200(slab|node=0|zone=1|lastcpupid=0x7ff) raw: 00fff00000000200 ffffea00005359c8 ffffea000094a188 ffff888011840800 raw: 0000000000000000 ffff88801a73f000 0000000100000001 0000000000000000 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 0, migratetype Unmovable, gfp_mask 0x2420c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_COMP|__GFP_THISNODE), pid 6333, tgid 6327 (syz-executor.2), ts 313540296523, free_ts 283803443997 prep_new_page mm/page_alloc.c:2538 [inline] get_page_from_freelist+0x10b5/0x2d50 mm/page_alloc.c:4287 __alloc_pages_slowpath.constprop.0+0x36b/0x23d0 mm/page_alloc.c:5088 __alloc_pages+0x4a6/0x5a0 mm/page_alloc.c:5567 __alloc_pages_node include/linux/gfp.h:223 [inline] kmem_getpages mm/slab.c:1363 [inline] cache_grow_begin+0x75/0x360 mm/slab.c:2570 cache_alloc_refill+0x27f/0x380 mm/slab.c:2943 ____cache_alloc mm/slab.c:3019 [inline] ____cache_alloc mm/slab.c:3002 [inline] __do_cache_alloc mm/slab.c:3202 [inline] slab_alloc_node mm/slab.c:3250 [inline] __kmem_cache_alloc_node+0x442/0x500 mm/slab.c:3549 __do_kmalloc_node mm/slab_common.c:954 [inline] __kmalloc+0x44/0xc0 mm/slab_common.c:968 kmalloc include/linux/slab.h:581 [inline] kzalloc include/linux/slab.h:712 [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 copy_namespaces+0x391/0x450 kernel/nsproxy.c:178 copy_process+0x306e/0x7190 kernel/fork.c:2256 kernel_clone+0xe7/0x980 kernel/fork.c:2671 __do_sys_clone3+0x1cd/0x2e0 kernel/fork.c:2970 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 page last free stack trace: reset_page_owner include/linux/page_owner.h:24 [inline] free_pages_prepare mm/page_alloc.c:1458 [inline] free_pcp_prepare+0x65c/0xd90 mm/page_alloc.c:1508 free_unref_page_prepare mm/page_alloc.c:3386 [inline] free_unref_page+0x19/0x4d0 mm/page_alloc.c:3482 slab_destroy mm/slab.c:1615 [inline] slabs_destroy+0x85/0xc0 mm/slab.c:1635 cache_flusharray mm/slab.c:3360 [inline] ___cache_free+0x2a8/0x3d0 mm/slab.c:3423 qlink_free mm/kasan/quarantine.c:168 [inline] qlist_free_all+0x4f/0x1a0 mm/kasan/quarantine.c:187 kasan_quarantine_reduce+0x180/0x200 mm/kasan/quarantine.c:294 __kasan_slab_alloc+0x5f/0x80 mm/kasan/common.c:302 kasan_slab_alloc include/linux/kasan.h:201 [inline] slab_post_alloc_hook mm/slab.h:737 [inline] slab_alloc_node mm/slab.c:3257 [inline] slab_alloc mm/slab.c:3265 [inline] __kmem_cache_alloc_lru mm/slab.c:3442 [inline] kmem_cache_alloc+0x218/0x450 mm/slab.c:3461 ptlock_alloc+0x1d/0x70 mm/memory.c:5842 ptlock_init include/linux/mm.h:2336 [inline] pgtable_pte_page_ctor include/linux/mm.h:2363 [inline] __pte_alloc_one include/asm-generic/pgalloc.h:66 [inline] pte_alloc_one+0x68/0x230 arch/x86/mm/pgtable.c:33 do_fault_around mm/memory.c:4518 [inline] do_read_fault mm/memory.c:4549 [inline] do_fault mm/memory.c:4683 [inline] handle_pte_fault mm/memory.c:4955 [inline] __handle_mm_fault+0x3151/0x3a40 mm/memory.c:5097 handle_mm_fault+0x1c8/0x780 mm/memory.c:5218 faultin_page mm/gup.c:1009 [inline] __get_user_pages+0x497/0xf10 mm/gup.c:1230 populate_vma_page_range+0x23d/0x320 mm/gup.c:1587 __mm_populate+0x101/0x3a0 mm/gup.c:1701 mm_populate include/linux/mm.h:2744 [inline] vm_mmap_pgoff+0x1fd/0x270 mm/util.c:525 Memory state around the buggy address: ffff88801a73f480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88801a73f500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff88801a73f580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88801a73f600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88801a73f680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ================================================================== ---------------- Code disassembly (best guess): 0: ff c9 dec %ecx 2: 75 f2 jne 0xfffffff6 4: 89 d1 mov %edx,%ecx 6: c1 e9 03 shr $0x3,%ecx 9: 83 e2 07 and $0x7,%edx c: f3 48 a5 rep movsq %ds:(%rsi),%es:(%rdi) f: 89 d1 mov %edx,%ecx 11: f3 a4 rep movsb %ds:(%rsi),%es:(%rdi) 13: 31 c0 xor %eax,%eax 15: 0f 1f 00 nopl (%rax) 18: c3 retq 19: 8d 0c ca lea (%rdx,%rcx,8),%ecx 1c: 89 ca mov %ecx,%edx 1e: eb 20 jmp 0x40 20: 0f 1f 00 nopl (%rax) 23: 83 fa 40 cmp $0x40,%edx 26: 72 38 jb 0x60 28: 89 d1 mov %edx,%ecx * 2a: f3 a4 rep movsb %ds:(%rsi),%es:(%rdi) <-- trapping instruction 2c: 31 c0 xor %eax,%eax 2e: 0f 1f 00 nopl (%rax) 31: c3 retq 32: 89 ca mov %ecx,%edx 34: eb 0a jmp 0x40 36: 66 2e 0f 1f 84 00 00 nopw %cs:0x0(%rax,%rax,1) 3d: 00 00 00