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BUG: KASAN: slab-out-of-bounds in mpol_parse_str+0x87b/0xa50 mm/mempolicy.c:2922
Write of size 1 at addr ffff88809fae80bf by task syz-executor264/10393

CPU: 1 PID: 10393 Comm: syz-executor264 Not tainted 5.5.0-rc5-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+0x197/0x210 lib/dump_stack.c:118
 print_address_description.constprop.0.cold+0xd4/0x30b mm/kasan/report.c:374
 __kasan_report.cold+0x1b/0x41 mm/kasan/report.c:506
 kasan_report+0x12/0x20 mm/kasan/common.c:639
 __asan_report_store1_noabort+0x17/0x20 mm/kasan/generic_report.c:137
 mpol_parse_str+0x87b/0xa50 mm/mempolicy.c:2922
 shmem_parse_one+0x71e/0xa40 mm/shmem.c:3472
 vfs_parse_fs_param+0x2ca/0x540 fs/fs_context.c:145
 vfs_parse_fs_string+0x105/0x170 fs/fs_context.c:188
 shmem_parse_options+0x168/0x250 mm/shmem.c:3522
 parse_monolithic_mount_data+0x69/0x90 fs/fs_context.c:704
 do_new_mount fs/namespace.c:2818 [inline]
 do_mount+0x1310/0x1b50 fs/namespace.c:3142
 __do_sys_mount fs/namespace.c:3351 [inline]
 __se_sys_mount fs/namespace.c:3328 [inline]
 __x64_sys_mount+0x192/0x230 fs/namespace.c:3328
 do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x446a9a
Code: b8 08 00 00 00 0f 05 48 3d 01 f0 ff ff 0f 83 7d ae fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 49 89 ca b8 a5 00 00 00 0f 05 <48> 3d 01 f0 ff ff 0f 83 5a ae fb ff c3 66 0f 1f 84 00 00 00 00 00
RSP: 002b:00007ffc02294f68 EFLAGS: 00000297 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007ffc02294f70 RCX: 0000000000446a9a
RDX: 00007ffc02294f70 RSI: 00000000200000c0 RDI: 00007ffc02294f90
RBP: 0000000000000003 R08: 00007ffc02294fd0 R09: 000000000000000a
R10: 0000000000000000 R11: 0000000000000297 R12: 00007ffc02294fd0
R13: 0000000000000004 R14: 0000000000000000 R15: 0000000000000000

Allocated by task 10225:
 save_stack+0x23/0x90 mm/kasan/common.c:72
 set_track mm/kasan/common.c:80 [inline]
 __kasan_kmalloc mm/kasan/common.c:513 [inline]
 __kasan_kmalloc.constprop.0+0xcf/0xe0 mm/kasan/common.c:486
 kasan_kmalloc+0x9/0x10 mm/kasan/common.c:527
 __do_kmalloc mm/slab.c:3656 [inline]
 __kmalloc+0x163/0x770 mm/slab.c:3665
 kmalloc include/linux/slab.h:561 [inline]
 tomoyo_add_entry security/tomoyo/common.c:2031 [inline]
 tomoyo_supervisor+0xb6b/0xef0 security/tomoyo/common.c:2103
 tomoyo_audit_env_log security/tomoyo/environ.c:36 [inline]
 tomoyo_env_perm+0x18e/0x210 security/tomoyo/environ.c:63
 tomoyo_environ security/tomoyo/domain.c:674 [inline]
 tomoyo_find_next_domain+0x1354/0x1f6c security/tomoyo/domain.c:881
 tomoyo_bprm_check_security security/tomoyo/tomoyo.c:107 [inline]
 tomoyo_bprm_check_security+0x124/0x1a0 security/tomoyo/tomoyo.c:97
 security_bprm_check+0x63/0xb0 security/security.c:784
 search_binary_handler+0x71/0x570 fs/exec.c:1645
 exec_binprm fs/exec.c:1701 [inline]
 __do_execve_file.isra.0+0x1329/0x22b0 fs/exec.c:1821
 do_execveat_common fs/exec.c:1867 [inline]
 do_execve fs/exec.c:1884 [inline]
 __do_sys_execve fs/exec.c:1960 [inline]
 __se_sys_execve fs/exec.c:1955 [inline]
 __x64_sys_execve+0x8f/0xc0 fs/exec.c:1955
 do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

Freed by task 10225:
 save_stack+0x23/0x90 mm/kasan/common.c:72
 set_track mm/kasan/common.c:80 [inline]
 kasan_set_free_info mm/kasan/common.c:335 [inline]
 __kasan_slab_free+0x102/0x150 mm/kasan/common.c:474
 kasan_slab_free+0xe/0x10 mm/kasan/common.c:483
 __cache_free mm/slab.c:3426 [inline]
 kfree+0x10a/0x2c0 mm/slab.c:3757
 tomoyo_add_entry security/tomoyo/common.c:2045 [inline]
 tomoyo_supervisor+0xc2c/0xef0 security/tomoyo/common.c:2103
 tomoyo_audit_env_log security/tomoyo/environ.c:36 [inline]
 tomoyo_env_perm+0x18e/0x210 security/tomoyo/environ.c:63
 tomoyo_environ security/tomoyo/domain.c:674 [inline]
 tomoyo_find_next_domain+0x1354/0x1f6c security/tomoyo/domain.c:881
 tomoyo_bprm_check_security security/tomoyo/tomoyo.c:107 [inline]
 tomoyo_bprm_check_security+0x124/0x1a0 security/tomoyo/tomoyo.c:97
 security_bprm_check+0x63/0xb0 security/security.c:784
 search_binary_handler+0x71/0x570 fs/exec.c:1645
 exec_binprm fs/exec.c:1701 [inline]
 __do_execve_file.isra.0+0x1329/0x22b0 fs/exec.c:1821
 do_execveat_common fs/exec.c:1867 [inline]
 do_execve fs/exec.c:1884 [inline]
 __do_sys_execve fs/exec.c:1960 [inline]
 __se_sys_execve fs/exec.c:1955 [inline]
 __x64_sys_execve+0x8f/0xc0 fs/exec.c:1955
 do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

The buggy address belongs to the object at ffff88809fae8080
 which belongs to the cache kmalloc-32 of size 32
The buggy address is located 31 bytes to the right of
 32-byte region [ffff88809fae8080, ffff88809fae80a0)
The buggy address belongs to the page:
page:ffffea00027eba00 refcount:1 mapcount:0 mapping:ffff8880aa4001c0 index:0xffff88809fae8fc1
raw: 00fffe0000000200 ffffea00029d8f08 ffffea00027e15c8 ffff8880aa4001c0
raw: ffff88809fae8fc1 ffff88809fae8000 0000000100000035 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff88809fae7f80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff88809fae8000: 00 00 fc fc fc fc fc fc fb fb fb fb fc fc fc fc
>ffff88809fae8080: fb fb fb fb fc fc fc fc 00 05 fc fc fc fc fc fc
                                        ^
 ffff88809fae8100: 00 00 00 fc fc fc fc fc fb fb fb fb fc fc fc fc
 ffff88809fae8180: fb fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc
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