linux-next boot error: WARNING in kmem_cache_free

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit:    5a94f5bc Add linux-next specific files for 20200621
git tree:       linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=12a02c76100000
kernel config:  https://syzkaller.appspot.com/x/.config?x=e1788c418b2ddc66
dashboard link: https://syzkaller.appspot.com/bug?extid=95bccd805a4aa06a4b0d
compiler:       gcc (GCC) 9.0.0 20181231 (experimental)

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+95bccd805a4aa06a4b0d@xxxxxxxxxxxxxxxxxxxxxxxxx

------------[ cut here ]------------
WARNING: CPU: 0 PID: 0 at mm/slab.h:232 kmem_cache_free+0x0/0x200 mm/slab.c:2262
Kernel panic - not syncing: panic_on_warn set ...
CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.8.0-rc1-next-20200621-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x18f/0x20d lib/dump_stack.c:118
 panic+0x2e3/0x75c kernel/panic.c:231
 __warn.cold+0x2f/0x3a kernel/panic.c:600
 report_bug+0x271/0x2f0 lib/bug.c:198
 exc_invalid_op+0x1b9/0x370 arch/x86/kernel/traps.c:235
 asm_exc_invalid_op+0x12/0x20 arch/x86/include/asm/idtentry.h:563
RIP: 0010:kmem_cache_debug_flags mm/slab.h:232 [inline]
RIP: 0010:cache_from_obj mm/slab.h:459 [inline]
RIP: 0010:kmem_cache_free+0x0/0x200 mm/slab.c:3678
Code: ff 49 c7 84 24 90 00 00 00 00 00 00 00 83 c3 01 39 1d 2c ec fb 08 77 af 5b 5d 41 5c 41 5d c3 90 66 2e 0f 1f 84 00 00 00 00 00 <0f> 0b 48 85 ff 0f 84 a9 01 00 00 48 83 3d 15 6b 02 08 00 0f 84 9c
RSP: 0000:ffffffff89a07a58 EFLAGS: 00010293
RAX: ffffffff89a86580 RBX: ffff8880aa01f0e8 RCX: ffffffff81a84573
RDX: 0000000000000000 RSI: ffff8880aa01f480 RDI: ffff8880aa00fe00
RBP: ffff8880aa01f4a8 R08: ffffffff89a86580 R09: fffffbfff1340f3f
R10: 0000000000000003 R11: fffffbfff1340f3e R12: ffff8880aa01f4b0
R13: ffff8880aa01f688 R14: ffff8880aa01f480 R15: ffffc90000000000
 adjust_va_to_fit_type mm/vmalloc.c:980 [inline]
 __alloc_vmap_area mm/vmalloc.c:1096 [inline]
 alloc_vmap_area+0x1494/0x1df0 mm/vmalloc.c:1196
 __get_vm_area_node+0x178/0x3b0 mm/vmalloc.c:2060
 __vmalloc_node_range+0x12c/0x910 mm/vmalloc.c:2484
 __vmalloc_node mm/vmalloc.c:2532 [inline]
 __vmalloc_area_node mm/vmalloc.c:2404 [inline]
 __vmalloc_node_range+0x76c/0x910 mm/vmalloc.c:2489
 __vmalloc_node mm/vmalloc.c:2532 [inline]
 __vmalloc+0x69/0x80 mm/vmalloc.c:2546
 alloc_large_system_hash+0x1c9/0x2e2 mm/page_alloc.c:8181
 inode_init+0xab/0xbc fs/inode.c:2099
 vfs_caches_init+0x104/0x11e fs/dcache.c:3231
 start_kernel+0x978/0x9fb init/main.c:1025
 secondary_startup_64+0xa4/0xb0 arch/x86/kernel/head_64.S:243


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