WARNING in __vunmap

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit:    a048a07d7f45 powerpc/64s: Add support for a store forwardi..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1418d5a7800000
kernel config:  https://syzkaller.appspot.com/x/.config?x=982e2df1b9e60b02
dashboard link: https://syzkaller.appspot.com/bug?extid=5ec9bb042ddfe9644773
compiler:       gcc (GCC) 8.0.1 20180413 (experimental)

Unfortunately, I don't have any reproducer for this crash yet.

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+5ec9bb042ddfe9644773@xxxxxxxxxxxxxxxxxxxxxxxxx

------------[ cut here ]------------
Trying to vfree() nonexistent vm area (0000000094b55709)
WARNING: CPU: 1 PID: 8605 at mm/vmalloc.c:1525 __vunmap+0x324/0x3c0  
mm/vmalloc.c:1524
Kernel panic - not syncing: panic_on_warn set ...

CPU: 1 PID: 8605 Comm: syz-executor7 Not tainted 4.17.0-rc6+ #63
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+0x1b9/0x294 lib/dump_stack.c:113
 panic+0x22f/0x4de kernel/panic.c:184
 __warn.cold.8+0x163/0x1b3 kernel/panic.c:536
 report_bug+0x252/0x2d0 lib/bug.c:186
 fixup_bug arch/x86/kernel/traps.c:178 [inline]
 do_error_trap+0x1de/0x490 arch/x86/kernel/traps.c:296
 do_invalid_op+0x1b/0x20 arch/x86/kernel/traps.c:315
 invalid_op+0x14/0x20 arch/x86/entry/entry_64.S:992
RIP: 0010:__vunmap+0x324/0x3c0 mm/vmalloc.c:1524
RSP: 0018:ffff88018273f2b0 EFLAGS: 00010286
RAX: 0000000000000038 RBX: 0000000000000000 RCX: ffffc90003ed8000
RDX: 0000000000003b55 RSI: ffffffff81610961 RDI: ffff88018273ee10
RBP: ffff88018273f2f0 R08: ffff8801ab1a0340 R09: 0000000000000006
R10: ffff8801ab1a0340 R11: 0000000000000000 R12: ffffc90014122000
R13: 0000000000000001 R14: fffffbfff12f7f76 R15: 000060fe24e7fae8
 vfree+0x68/0x100 mm/vmalloc.c:1606
 ipcomp_free_scratches+0xbb/0x150 net/xfrm/xfrm_ipcomp.c:216
 ipcomp_free_data net/xfrm/xfrm_ipcomp.c:325 [inline]
 ipcomp_init_state+0x8cf/0xc00 net/xfrm/xfrm_ipcomp.c:377
 ipcomp4_init_state+0x110/0xb30 net/ipv4/ipcomp.c:137
 __xfrm_init_state+0x60e/0x1030 net/xfrm/xfrm_state.c:2277
 xfrm_init_state+0x1e/0x80 net/xfrm/xfrm_state.c:2303
 pfkey_msg2xfrm_state net/key/af_key.c:1307 [inline]
 pfkey_add+0x1c86/0x2eb0 net/key/af_key.c:1524
 pfkey_process+0x83d/0x980 net/key/af_key.c:2844
 pfkey_sendmsg+0x5f4/0x1050 net/key/af_key.c:3683
 sock_sendmsg_nosec net/socket.c:629 [inline]
 sock_sendmsg+0xd5/0x120 net/socket.c:639
 ___sys_sendmsg+0x805/0x940 net/socket.c:2117
 __sys_sendmsg+0x115/0x270 net/socket.c:2155
 __do_sys_sendmsg net/socket.c:2164 [inline]
 __se_sys_sendmsg net/socket.c:2162 [inline]
 __x64_sys_sendmsg+0x78/0xb0 net/socket.c:2162
 do_syscall_64+0x1b1/0x800 arch/x86/entry/common.c:287
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x455a09
RSP: 002b:00007fe6fd709c68 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007fe6fd70a6d4 RCX: 0000000000455a09
RDX: 0000000000000000 RSI: 0000000020f56000 RDI: 0000000000000014
RBP: 000000000072bea0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 000000000000059d R14: 00000000006fc758 R15: 0000000000000000
Dumping ftrace buffer:
   (ftrace buffer empty)
Kernel Offset: disabled
Rebooting in 86400 seconds..


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