KASAN: slab-use-after-free Read in madvise

ID	Workflow	Result	Correct	Bug	Created	Started	Finished	Revision	Error
8d979f77-6838-4698-a513-eeb2d0214042	assessment-security		💥	KASAN: slab-use-after-free Read in madvise_collapse	2026/05/17 05:34	2026/05/17 05:34	2026/05/17 05:54	de5aae85e5f28e2fa1c7deefcc24fe286abe5140	failed to run ["make" "KERNELVERSION=syzkaller" "KERNELRELEASE=syzkaller" "LOCALVERSION=-syzkaller" "-j" "32" "ARCH=x86_64" "CC=ccache clang" "LD=ld.lld" "O=/app/workdir/cache/build/3d5252f3447edc39d33fb2b0e2cfcb5462a6d6c6" "-s" "bzImage" "compile_commands.json"]: exit status 2 Root cause: include/linux/thread_info.h:244:4: error: call to '__bad_copy_from' declared with 'error' attribute: copy source size is too small * * Restart config... * * * General architecture-dependent options * Kprobes (KPROBES) [N/y/?] n Optimize very unlikely/likely branches (JUMP_LABEL) [Y/n/?] y Static key selftest (STATIC_KEYS_SELFTEST) [N/y/?] n Static call selftest (STATIC_CALL_SELFTEST) [N/y/?] n Enable seccomp to safely execute untrusted bytecode (SECCOMP) [Y/n/?] y Show seccomp filter cache status in /proc/pid/seccomp_cache (SECCOMP_CACHE_DEBUG) [N/y/?] n Link Time Optimization (LTO) > 1. None (LTO_NONE) choice[1]: 1 Use Clang's Control Flow Integrity (CFI) (CFI_CLANG) [N/y/?] (NEW) Error in reading or end of file. Number of bits to use for ASLR of mmap base address (ARCH_MMAP_RND_BITS) [28] 28 Number of bits to use for ASLR of mmap base address for compatible applications (ARCH_MMAP_RND_COMPAT_BITS) [8] 8 Provide system calls for 32-bit time_t (COMPAT_32BIT_TIME) [Y/n/?] y Use a virtually-mapped stack (VMAP_STACK) [Y/n/?] y Support for randomizing kernel stack offset on syscall entry (RANDOMIZE_KSTACK_OFFSET) [Y/n/?] y Default state of kernel stack offset randomization (RANDOMIZE_KSTACK_OFFSET_DEFAULT) [N/y/?] n Locking event counts collection (LOCK_EVENT_COUNTS) [N/y/?] n * * Kernel hardening options * Randomize layout of sensitive kernel structures > 1. Disable structure layout randomization (RANDSTRUCT_NONE) 2. Fully randomize structure layout (RANDSTRUCT_FULL) (NEW) choice[1-2?]: Error in reading or end of file. * * Compile-time checks and compiler options * Debug information 1. Disable debug information (DEBUG_INFO_NONE) 2. Rely on the toolchain's implicit default DWARF version (DEBUG_INFO_DWARF_TOOLCHAIN_DEFAULT) > 3. Generate DWARF Version 4 debuginfo (DEBUG_INFO_DWARF4) 4. Generate DWARF Version 5 debuginfo (DEBUG_INFO_DWARF5) choice[1-4?]: 3 Reduce debugging information (DEBUG_INFO_REDUCED) [N/y/?] n Compressed Debug information > 1. Don't compress debug information (DEBUG_INFO_COMPRESSED_NONE) 2. Compress debugging information with zlib (DEBUG_INFO_COMPRESSED_ZLIB) 3. Compress debugging information with zstd (DEBUG_INFO_COMPRESSED_ZSTD) (NEW) choice[1-3?]: Error in reading or end of file. Produce split debuginfo in .dwo files (DEBUG_INFO_SPLIT) [N/y/?] n Generate BTF typeinfo (DEBUG_INFO_BTF) [N/y/?] n Provide GDB scripts for kernel debugging (GDB_SCRIPTS) [N/y/?] n Warn for stack frames larger than (FRAME_WARN) [2048] 2048 Strip assembler-generated symbols during link (STRIP_ASM_SYMS) [N/y/?] n Install uapi headers to usr/include (HEADERS_INSTALL) [N/y/?] n Make section mismatch errors non-fatal (SECTION_MISMATCH_WARN_ONLY) [Y/n/?] y Force all function address 64B aligned (DEBUG_FORCE_FUNCTION_ALIGN_64B) [N/y/?] n Generate vmlinux.map file when linking (VMLINUX_MAP) [N/y/?] n Force weak per-cpu definitions (DEBUG_FORCE_WEAK_PER_CPU) [N/y/?] n In file included from /app/workdir/cache/src/ed808b7d0e91e2ec6a9b3064ccf77afa613dd19a/arch/x86/kernel/asm-offsets.c:14: In file included from /app/workdir/cache/src/ed808b7d0e91e2ec6a9b3064ccf77afa613dd19a/include/linux/suspend.h:5: In file included from /app/workdir/cache/src/ed808b7d0e91e2ec6a9b3064ccf77afa613dd19a/include/linux/swap.h:9: In file included from /app/workdir/cache/src/ed808b7d0e91e2ec6a9b3064ccf77afa613dd19a/include/linux/memcontrol.h:20: In file included from /app/workdir/cache/src/ed808b7d0e91e2ec6a9b3064ccf77afa613dd19a/include/linux/mm.h:2139: /app/workdir/cache/src/ed808b7d0e91e2ec6a9b3064ccf77afa613dd19a/include/linux/vmstat.h:508:43: warning: arithmetic between different enumeration types ('enum zone_stat_item' and 'enum numa_stat_item') [-Wenum-enum-conversion] 508 \| return vmstat_text[NR_VM_ZONE_STAT_ITEMS + \|

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[syzbot] [mm?] KASAN: slab-use-after-free Read in madvise_collapse	1 (2)	2023/07/23 22:43
[PATCH v3 10/13 fix] mm/khugepaged: collapse_pte_mapped_thp() with mmap_read_lock(): fix	1 (1)	2023/07/23 22:32

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[syzbot] [mm?] KASAN: slab-use-after-free Read in madvise_collapse

1 (2)

2023/07/23 22:43

[PATCH v3 10/13 fix] mm/khugepaged: collapse_pte_mapped_thp() with mmap_read_lock(): fix

1 (1)

2023/07/23 22:32

================================================================== BUG: KASAN: slab-use-after-free in madvise_collapse+0xa6c/0xb50 mm/khugepaged.c:2723 Read of size 8 at addr ffff88802b4e6588 by task syz-executor296/5046 CPU: 0 PID: 5046 Comm: syz-executor296 Not tainted 6.5.0-rc2-next-20230721-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2023 Call Trace: <TASK> __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xd9/0x1b0 lib/dump_stack.c:106 print_address_description mm/kasan/report.c:364 [inline] print_report+0xc4/0x620 mm/kasan/report.c:475 kasan_report+0xda/0x110 mm/kasan/report.c:588 madvise_collapse+0xa6c/0xb50 mm/khugepaged.c:2723 madvise_vma_behavior+0x200/0x1e60 mm/madvise.c:1094 madvise_walk_vmas+0x1cf/0x2c0 mm/madvise.c:1268 do_madvise+0x333/0x660 mm/madvise.c:1448 __do_sys_madvise mm/madvise.c:1461 [inline] __se_sys_madvise mm/madvise.c:1459 [inline] __x64_sys_madvise+0xaa/0x110 mm/madvise.c:1459 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x38/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd RIP: 0033:0x7f7ec298d359 Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 51 18 00 00 90 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 b0 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f7ec292d238 EFLAGS: 00000246 ORIG_RAX: 000000000000001c RAX: ffffffffffffffda RBX: 00007f7ec2a17318 RCX: 00007f7ec298d359 RDX: 0000000000000019 RSI: 000000000060005f RDI: 0000000020000000 RBP: 00007f7ec2a17310 R08: 00007fffd329edf7 R09: 00007f7ec292d6c0 R10: 0000000000000000 R11: 0000000000000246 R12: b635773f07ebbeea R13: 000000000000006e R14: 00007fffd329ed10 R15: 00007fffd329edf8 </TASK> Allocated by task 5033: kasan_save_stack+0x33/0x50 mm/kasan/common.c:45 kasan_set_track+0x25/0x30 mm/kasan/common.c:52 __kasan_slab_alloc+0x81/0x90 mm/kasan/common.c:328 kasan_slab_alloc include/linux/kasan.h:186 [inline] slab_post_alloc_hook mm/slab.h:762 [inline] slab_alloc_node mm/slub.c:3478 [inline] slab_alloc mm/slub.c:3486 [inline] __kmem_cache_alloc_lru mm/slub.c:3493 [inline] kmem_cache_alloc+0x172/0x3b0 mm/slub.c:3502 vm_area_alloc+0x1f/0x220 kernel/fork.c:485 mmap_region+0x386/0x2640 mm/mmap.c:2717 do_mmap+0x87c/0xed0 mm/mmap.c:1353 vm_mmap_pgoff+0x1a6/0x3b0 mm/util.c:543 ksys_mmap_pgoff+0x7d/0x5b0 mm/mmap.c:1399 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x38/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd Freed by task 5035: kasan_save_stack+0x33/0x50 mm/kasan/common.c:45 kasan_set_track+0x25/0x30 mm/kasan/common.c:52 kasan_save_free_info+0x2b/0x40 mm/kasan/generic.c:522 ____kasan_slab_free mm/kasan/common.c:236 [inline] ____kasan_slab_free+0x15e/0x1b0 mm/kasan/common.c:200 kasan_slab_free include/linux/kasan.h:162 [inline] slab_free_hook mm/slub.c:1800 [inline] slab_free_freelist_hook+0x114/0x1e0 mm/slub.c:1826 slab_free mm/slub.c:3809 [inline] kmem_cache_free+0xf0/0x490 mm/slub.c:3831 rcu_do_batch kernel/rcu/tree.c:2139 [inline] rcu_core+0x7fb/0x1bb0 kernel/rcu/tree.c:2403 __do_softirq+0x218/0x965 kernel/softirq.c:553 Last potentially related work creation: kasan_save_stack+0x33/0x50 mm/kasan/common.c:45 __kasan_record_aux_stack+0xbc/0xd0 mm/kasan/generic.c:492 __call_rcu_common.constprop.0+0x9a/0x790 kernel/rcu/tree.c:2653 remove_vma+0x140/0x170 mm/mmap.c:148 remove_mt mm/mmap.c:2285 [inline] do_vmi_align_munmap+0xf75/0x1710 mm/mmap.c:2547 do_vmi_munmap+0x20e/0x450 mm/mmap.c:2611 mmap_region+0x194/0x2640 mm/mmap.c:2661 do_mmap+0x87c/0xed0 mm/mmap.c:1353 vm_mmap_pgoff+0x1a6/0x3b0 mm/util.c:543 ksys_mmap_pgoff+0x7d/0x5b0 mm/mmap.c:1399 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x38/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd The buggy address belongs to the object at ffff88802b4e6500 which belongs to the cache vm_area_struct of size 192 The buggy address is located 136 bytes inside of freed 192-byte region [ffff88802b4e6500, ffff88802b4e65c0) The buggy address belongs to the physical page: page:ffffea0000ad3980 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x2b4e6 flags: 0xfff00000000200(slab|node=0|zone=1|lastcpupid=0x7ff) page_type: 0xffffffff() raw: 00fff00000000200 ffff888014674b40 ffffea0001dce680 dead000000000002 raw: 0000000000000000 0000000000100010 00000001ffffffff 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 0x12cc0(GFP_KERNEL|__GFP_NOWARN|__GFP_NORETRY), pid 4724, tgid 4724 (dhcpcd-run-hook), ts 33134643925, free_ts 33125953991 set_page_owner include/linux/page_owner.h:31 [inline] post_alloc_hook+0x2d2/0x350 mm/page_alloc.c:1569 prep_new_page mm/page_alloc.c:1576 [inline] get_page_from_freelist+0x10d7/0x31b0 mm/page_alloc.c:3256 __alloc_pages+0x1d0/0x4a0 mm/page_alloc.c:4512 alloc_pages+0x1a9/0x270 mm/mempolicy.c:2279 alloc_slab_page mm/slub.c:1870 [inline] allocate_slab+0x24e/0x380 mm/slub.c:2017 new_slab mm/slub.c:2070 [inline] ___slab_alloc+0x8bc/0x1570 mm/slub.c:3223 __slab_alloc.constprop.0+0x56/0xa0 mm/slub.c:3322 __slab_alloc_node mm/slub.c:3375 [inline] slab_alloc_node mm/slub.c:3468 [inline] slab_alloc mm/slub.c:3486 [inline] __kmem_cache_alloc_lru mm/slub.c:3493 [inline] kmem_cache_alloc+0x392/0x3b0 mm/slub.c:3502 vm_area_alloc+0x1f/0x220 kernel/fork.c:485 mmap_region+0x386/0x2640 mm/mmap.c:2717 do_mmap+0x87c/0xed0 mm/mmap.c:1353 vm_mmap_pgoff+0x1a6/0x3b0 mm/util.c:543 ksys_mmap_pgoff+0x422/0x5b0 mm/mmap.c:1399 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x38/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd page last free stack trace: reset_page_owner include/linux/page_owner.h:24 [inline] free_pages_prepare mm/page_alloc.c:1160 [inline] free_unref_page_prepare+0x508/0xb90 mm/page_alloc.c:2383 free_unref_page+0x33/0x3b0 mm/page_alloc.c:2478 vfree+0x181/0x7a0 mm/vmalloc.c:2842 delayed_vfree_work+0x56/0x70 mm/vmalloc.c:2763 process_one_work+0xaa2/0x16f0 kernel/workqueue.c:2600 worker_thread+0x687/0x1110 kernel/workqueue.c:2751 kthread+0x33a/0x430 kernel/kthread.c:389 ret_from_fork+0x2c/0x70 arch/x86/kernel/process.c:145 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:296 Memory state around the buggy address: ffff88802b4e6480: 00 00 00 00 00 00 00 00 fc fc fc fc fc fc fc fc ffff88802b4e6500: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff88802b4e6580: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc ^ ffff88802b4e6600: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffff88802b4e6680: 00 00 00 00 00 00 00 00 fc fc fc fc fc fc fc fc ==================================================================

Crashes (5):
Time	Kernel	Commit	Syzkaller	Config	Log	Report	Syz repro	C repro	VM info	Assets (help?)	Manager	Title
2023/07/23 09:04	linux-next	ae867bc97b71	27cbe77f	.config	console log	report	syz	C		[disk image] [vmlinux] [kernel image]	ci-upstream-linux-next-kasan-gce-root	KASAN: slab-use-after-free Read in madvise_collapse
2023/07/24 00:30	linux-next	ae867bc97b71	27cbe77f	.config	console log	report			info	[disk image] [vmlinux] [kernel image]	ci-upstream-linux-next-kasan-gce-root	KASAN: slab-use-after-free Read in madvise_collapse
2023/07/22 17:41	linux-next	ae867bc97b71	27cbe77f	.config	console log	report			info	[disk image] [vmlinux] [kernel image]	ci-upstream-linux-next-kasan-gce-root	KASAN: slab-use-after-free Read in madvise_collapse
2023/07/18 23:57	linux-next	aeba456828b4	022df2bb	.config	console log	report			info	[disk image] [vmlinux] [kernel image]	ci-upstream-linux-next-kasan-gce-root	KASAN: slab-use-after-free Read in madvise_collapse
2023/07/18 23:37	linux-next	aeba456828b4	022df2bb	.config	console log	report			info	[disk image] [vmlinux] [kernel image]	ci-upstream-linux-next-kasan-gce-root	KASAN: slab-use-after-free Read in madvise_collapse

Crashes (5):

Assets (help?)