general protection fault in free_swap_cache

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit:    92ed3019 Linux 5.8-rc7
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=15702138900000
kernel config:  https://syzkaller.appspot.com/x/.config?x=84f076779e989e69
dashboard link: https://syzkaller.appspot.com/bug?extid=10e0e0681594086f6872
compiler:       gcc (GCC) 10.1.0-syz 20200507
userspace arch: i386

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

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+10e0e0681594086f6872@xxxxxxxxxxxxxxxxxxxxxxxxx

general protection fault, probably for non-canonical address 0xdffffc000043a5d1: 0000 [#1] PREEMPT SMP KASAN
KASAN: probably user-memory-access in range [0x00000000021d2e88-0x00000000021d2e8f]
CPU: 1 PID: 31709 Comm: syz-executor.1 Not tainted 5.8.0-rc7-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:compound_head include/linux/page-flags.h:182 [inline]
RIP: 0010:PageSwapCache include/linux/page-flags.h:391 [inline]
RIP: 0010:free_swap_cache+0x28/0x300 mm/swap_state.c:266
Code: c3 90 41 57 41 56 41 55 41 54 49 89 fc 55 4d 8d 6c 24 08 53 e8 49 b3 c7 ff 4c 89 ea 48 b8 00 00 00 00 00 fc ff df 48 c1 ea 03 <80> 3c 02 00 0f 85 85 02 00 00 4d 8b 74 24 08 31 ff 4c 89 e5 4c 89
RSP: 0018:ffffc9001831f900 EFLAGS: 00010206
RAX: dffffc0000000000 RBX: ffff888000163028 RCX: ffffffff81ac3992
RDX: 000000000043a5d1 RSI: ffffffff81ac0987 RDI: 00000000021d2e80
RBP: 0000000000000003 R08: 0000000000000000 R09: ffffea00021d2e47
R10: 00000000000001fe R11: 0000000000000000 R12: 00000000021d2e80
R13: 00000000021d2e88 R14: dffffc0000000000 R15: ffffc9001831fcb0
FS:  0000000000000000(0000) GS:ffff8880ae700000(0000) knlGS:0000000000000000
CS:  0010 DS: 002b ES: 002b CR0: 0000000080050033
CR2: 0000000008157854 CR3: 0000000092a01000 CR4: 00000000001426e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 free_pages_and_swap_cache+0x58/0x90 mm/swap_state.c:294
 tlb_batch_pages_flush mm/mmu_gather.c:49 [inline]
 tlb_flush_mmu_free mm/mmu_gather.c:242 [inline]
 tlb_flush_mmu+0xe9/0x6b0 mm/mmu_gather.c:249
 zap_pte_range mm/memory.c:1155 [inline]
 zap_pmd_range mm/memory.c:1193 [inline]
 zap_pud_range mm/memory.c:1222 [inline]
 zap_p4d_range mm/memory.c:1243 [inline]
 unmap_page_range+0x1bd4/0x2940 mm/memory.c:1264
 unmap_single_vma+0x198/0x300 mm/memory.c:1309
 unmap_vmas+0x16f/0x2f0 mm/memory.c:1341
 exit_mmap+0x2b1/0x510 mm/mmap.c:3162
 __mmput+0x122/0x470 kernel/fork.c:1093
 mmput+0x53/0x60 kernel/fork.c:1114
 exit_mm kernel/exit.c:482 [inline]
 do_exit+0xa8f/0x2a40 kernel/exit.c:792
 do_group_exit+0x125/0x310 kernel/exit.c:903
 __do_sys_exit_group kernel/exit.c:914 [inline]
 __se_sys_exit_group kernel/exit.c:912 [inline]
 __ia32_sys_exit_group+0x3a/0x50 kernel/exit.c:912
 do_syscall_32_irqs_on+0x3f/0x60 arch/x86/entry/common.c:428
 __do_fast_syscall_32 arch/x86/entry/common.c:475 [inline]
 do_fast_syscall_32+0x7f/0x120 arch/x86/entry/common.c:503
 entry_SYSENTER_compat_after_hwframe+0x4d/0x5c
RIP: 0023:0xf7fec569
Code: Bad RIP value.
RSP: 002b:00000000086afd7c EFLAGS: 00000202 ORIG_RAX: 00000000000000fc
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000000001
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 000000000805a92b
RBP: 00000000fffffff7 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
Modules linked in:
---[ end trace 58b8e3320e616211 ]---
RIP: 0010:compound_head include/linux/page-flags.h:182 [inline]
RIP: 0010:PageSwapCache include/linux/page-flags.h:391 [inline]
RIP: 0010:free_swap_cache+0x28/0x300 mm/swap_state.c:266
Code: c3 90 41 57 41 56 41 55 41 54 49 89 fc 55 4d 8d 6c 24 08 53 e8 49 b3 c7 ff 4c 89 ea 48 b8 00 00 00 00 00 fc ff df 48 c1 ea 03 <80> 3c 02 00 0f 85 85 02 00 00 4d 8b 74 24 08 31 ff 4c 89 e5 4c 89
RSP: 0018:ffffc9001831f900 EFLAGS: 00010206
RAX: dffffc0000000000 RBX: ffff888000163028 RCX: ffffffff81ac3992
RDX: 000000000043a5d1 RSI: ffffffff81ac0987 RDI: 00000000021d2e80
RBP: 0000000000000003 R08: 0000000000000000 R09: ffffea00021d2e47
R10: 00000000000001fe R11: 0000000000000000 R12: 00000000021d2e80
R13: 00000000021d2e88 R14: dffffc0000000000 R15: ffffc9001831fcb0
FS:  0000000000000000(0000) GS:ffff8880ae600000(0000) knlGS:0000000000000000
CS:  0010 DS: 002b ES: 002b CR0: 0000000080050033
CR2: 000000002ef2a000 CR3: 00000000932f4000 CR4: 00000000001426f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400


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