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BUG: KASAN: use-after-free in strcmp+0x9b/0xb0 lib/string.c:346
Read of size 1 at addr ffff888012f86504 by task syz-executor365/3595

CPU: 1 PID: 3595 Comm: syz-executor365 Not tainted 5.17.0-rc3-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106
 print_address_description.constprop.0.cold+0x8d/0x336 mm/kasan/report.c:255
 __kasan_report mm/kasan/report.c:442 [inline]
 kasan_report.cold+0x83/0xdf mm/kasan/report.c:459
 strcmp+0x9b/0xb0 lib/string.c:346
 replace_vma_anon_name mm/madvise.c:141 [inline]
 madvise_update_vma+0x4e6/0x7f0 mm/madvise.c:212
 madvise_vma_behavior+0x116/0x1910 mm/madvise.c:1043
 madvise_walk_vmas+0x1d5/0x2d0 mm/madvise.c:1207
 do_madvise mm/madvise.c:1385 [inline]
 do_madvise+0x249/0x3c0 mm/madvise.c:1343
 __do_sys_madvise mm/madvise.c:1398 [inline]
 __se_sys_madvise mm/madvise.c:1396 [inline]
 __x64_sys_madvise+0xa6/0x110 mm/madvise.c:1396
 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+0x44/0xae
RIP: 0033:0x7f2656061ff9
Code: 28 c3 e8 2a 14 00 00 66 2e 0f 1f 84 00 00 00 00 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 c0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffd2b728f88 EFLAGS: 00000246 ORIG_RAX: 000000000000001c
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f2656061ff9
RDX: 000000000000000b RSI: 0000000000001000 RDI: 0000000020ffc000
RBP: 00007f2656025fe0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000020000000 R11: 0000000000000246 R12: 00007f2656026070
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
 </TASK>

Allocated by task 3595:
 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:436 [inline]
 ____kasan_kmalloc mm/kasan/common.c:515 [inline]
 ____kasan_kmalloc mm/kasan/common.c:474 [inline]
 __kasan_kmalloc+0xa9/0xd0 mm/kasan/common.c:524
 kmalloc include/linux/slab.h:586 [inline]
 anon_vma_name_alloc mm/madvise.c:75 [inline]
 replace_vma_anon_name mm/madvise.c:146 [inline]
 madvise_update_vma+0x546/0x7f0 mm/madvise.c:212
 madvise_vma_anon_name+0x7c/0xc0 mm/madvise.c:1236
 madvise_walk_vmas+0x1d5/0x2d0 mm/madvise.c:1207
 madvise_set_anon_name+0xac/0xe0 mm/madvise.c:1269
 prctl_set_vma kernel/sys.c:2305 [inline]
 __do_sys_prctl+0xeb5/0x12d0 kernel/sys.c:2594
 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+0x44/0xae

Freed by task 3595:
 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:366 [inline]
 ____kasan_slab_free+0x130/0x160 mm/kasan/common.c:328
 kasan_slab_free include/linux/kasan.h:236 [inline]
 slab_free_hook mm/slub.c:1728 [inline]
 slab_free_freelist_hook+0x8b/0x1c0 mm/slub.c:1754
 slab_free mm/slub.c:3509 [inline]
 kfree+0xcb/0x280 mm/slub.c:4562
 vma_anon_name_free mm/madvise.c:88 [inline]
 kref_put include/linux/kref.h:65 [inline]
 free_vma_anon_name mm/madvise.c:125 [inline]
 free_vma_anon_name+0xeb/0x110 mm/madvise.c:116
 vm_area_free+0x11/0x30 kernel/fork.c:376
 __vma_adjust+0x836/0x24a0 mm/mmap.c:962
 vma_merge+0x860/0xeb0 mm/mmap.c:1217
 madvise_update_vma+0x1b6/0x7f0 mm/madvise.c:180
 madvise_vma_behavior+0x116/0x1910 mm/madvise.c:1043
 madvise_walk_vmas+0x1d5/0x2d0 mm/madvise.c:1207
 do_madvise mm/madvise.c:1385 [inline]
 do_madvise+0x249/0x3c0 mm/madvise.c:1343
 __do_sys_madvise mm/madvise.c:1398 [inline]
 __se_sys_madvise mm/madvise.c:1396 [inline]
 __x64_sys_madvise+0xa6/0x110 mm/madvise.c:1396
 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+0x44/0xae

The buggy address belongs to the object at ffff888012f86500
 which belongs to the cache kmalloc-32 of size 32
The buggy address is located 4 bytes inside of
 32-byte region [ffff888012f86500, ffff888012f86520)
The buggy address belongs to the page:
page:ffffea00004be180 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x12f86
flags: 0xfff00000000200(slab|node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000000200 ffffea00008dcb40 dead000000000002 ffff888010c41500
raw: 0000000000000000 0000000080400040 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 1, ts 2233967433, free_ts 0
 prep_new_page mm/page_alloc.c:2434 [inline]
 get_page_from_freelist+0xa72/0x2f50 mm/page_alloc.c:4165
 __alloc_pages+0x1b2/0x500 mm/page_alloc.c:5389
 alloc_page_interleave+0x1e/0x200 mm/mempolicy.c:2116
 alloc_pages+0x2b1/0x310 mm/mempolicy.c:2266
 alloc_slab_page mm/slub.c:1799 [inline]
 allocate_slab mm/slub.c:1944 [inline]
 new_slab+0x28a/0x3b0 mm/slub.c:2004
 ___slab_alloc+0x87c/0xe90 mm/slub.c:3018
 __slab_alloc.constprop.0+0x4d/0xa0 mm/slub.c:3105
 slab_alloc_node mm/slub.c:3196 [inline]
 slab_alloc mm/slub.c:3238 [inline]
 __kmalloc_track_caller+0x2e7/0x320 mm/slub.c:4926
 __do_krealloc mm/slab_common.c:1184 [inline]
 krealloc+0x87/0xf0 mm/slab_common.c:1217
 add_sysfs_param+0x152/0x960 kernel/params.c:660
 kernel_add_sysfs_param kernel/params.c:812 [inline]
 param_sysfs_builtin kernel/params.c:851 [inline]
 param_sysfs_init+0x301/0x43b kernel/params.c:970
 do_one_initcall+0x103/0x650 init/main.c:1300
 do_initcall_level init/main.c:1373 [inline]
 do_initcalls init/main.c:1389 [inline]
 do_basic_setup init/main.c:1408 [inline]
 kernel_init_freeable+0x6b1/0x73a init/main.c:1613
 kernel_init+0x1a/0x1d0 init/main.c:1502
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
page_owner free stack trace missing

Memory state around the buggy address:
 ffff888012f86400: 00 00 00 00 fc fc fc fc fb fb fb fb fc fc fc fc
 ffff888012f86480: 00 00 00 05 fc fc fc fc 00 00 00 00 fc fc fc fc
>ffff888012f86500: fa fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc
                   ^
 ffff888012f86580: 00 00 00 00 fc fc fc fc 00 00 00 00 fc fc fc fc
 ffff888012f86600: fb fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc
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