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BUG: KASAN: slab-out-of-bounds in decode_data.part.1+0x23c/0x280 drivers/net/hamradio/6pack.c:843
Write of size 1 at addr ffff88809622f04e by task kworker/u4:6/434

CPU: 0 PID: 434 Comm: kworker/u4:6 Not tainted 5.5.0-rc7-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: events_unbound flush_to_ldisc
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x12d/0x187 lib/dump_stack.c:118
 print_address_description.constprop.8.cold.10+0x9/0x31d mm/kasan/report.c:374
 __kasan_report.cold.11+0x1b/0x3a 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
 decode_data.part.1+0x23c/0x280 drivers/net/hamradio/6pack.c:843
 decode_data drivers/net/hamradio/6pack.c:965 [inline]
 sixpack_decode drivers/net/hamradio/6pack.c:968 [inline]
 sixpack_receive_buf+0x7a8/0x12c0 drivers/net/hamradio/6pack.c:458
 tty_ldisc_receive_buf+0xff/0x1b0 drivers/tty/tty_buffer.c:465
 tty_port_default_receive_buf+0x5f/0x90 drivers/tty/tty_port.c:38
 receive_buf drivers/tty/tty_buffer.c:481 [inline]
 flush_to_ldisc+0x1aa/0x3a0 drivers/tty/tty_buffer.c:533
 process_one_work+0x856/0x1630 kernel/workqueue.c:2264
 worker_thread+0x85/0xb60 kernel/workqueue.c:2410
 kthread+0x331/0x3f0 kernel/kthread.c:255
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352

Allocated by task 8294:
 save_stack+0x21/0x90 mm/kasan/common.c:72
 set_track mm/kasan/common.c:80 [inline]
 __kasan_kmalloc.constprop.17+0xc7/0xd0 mm/kasan/common.c:513
 kasan_kmalloc+0x9/0x10 mm/kasan/common.c:527
 __do_kmalloc_node mm/slab.c:3616 [inline]
 __kmalloc_node+0x4d/0x70 mm/slab.c:3623
 kmalloc_node include/linux/slab.h:579 [inline]
 kvmalloc_node+0x6a/0x80 mm/util.c:574
 kvmalloc include/linux/mm.h:655 [inline]
 kvzalloc include/linux/mm.h:663 [inline]
 alloc_netdev_mqs+0x5d/0xca0 net/core/dev.c:9732
 sixpack_open+0xe0/0x9fb drivers/net/hamradio/6pack.c:563
 tty_ldisc_open.isra.3+0x78/0xc0 drivers/tty/tty_ldisc.c:464
 tty_set_ldisc+0x238/0x5b0 drivers/tty/tty_ldisc.c:591
 tiocsetd drivers/tty/tty_io.c:2337 [inline]
 tty_ioctl+0x332/0x12f0 drivers/tty/tty_io.c:2597
 vfs_ioctl fs/ioctl.c:47 [inline]
 file_ioctl fs/ioctl.c:545 [inline]
 do_vfs_ioctl+0x196/0x1190 fs/ioctl.c:732
 ksys_ioctl+0x62/0x90 fs/ioctl.c:749
 __do_sys_ioctl fs/ioctl.c:756 [inline]
 __se_sys_ioctl fs/ioctl.c:754 [inline]
 __x64_sys_ioctl+0x6e/0xb0 fs/ioctl.c:754
 do_syscall_64+0xca/0x5f0 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

Freed by task 7990:
 save_stack+0x21/0x90 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+0x108/0x2c0 mm/slab.c:3757
 tomoyo_realpath_from_path+0x154/0x620 security/tomoyo/realpath.c:289
 tomoyo_get_realpath security/tomoyo/file.c:151 [inline]
 tomoyo_path_perm+0x203/0x380 security/tomoyo/file.c:822
 tomoyo_inode_getattr+0x13/0x20 security/tomoyo/tomoyo.c:129
 security_inode_getattr+0xb0/0x100 security/security.c:1222
 vfs_getattr+0x1c/0x40 fs/stat.c:115
 vfs_statx+0xd8/0x150 fs/stat.c:191
 vfs_stat include/linux/fs.h:3249 [inline]
 __do_sys_newstat+0x85/0xe0 fs/stat.c:341
 __se_sys_newstat fs/stat.c:337 [inline]
 __x64_sys_newstat+0x4f/0x70 fs/stat.c:337
 do_syscall_64+0xca/0x5f0 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

The buggy address belongs to the object at ffff88809622e000
 which belongs to the cache kmalloc-4k of size 4096
The buggy address is located 78 bytes to the right of
 4096-byte region [ffff88809622e000, ffff88809622f000)
The buggy address belongs to the page:
page:ffffea0002588b80 refcount:1 mapcount:0 mapping:ffff8880aa402000 index:0x0 compound_mapcount: 0
raw: 00fffe0000010200 ffffea00025fd588 ffffea00024eaa08 ffff8880aa402000
raw: 0000000000000000 ffff88809622e000 0000000100000001 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff88809622ef00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88809622ef80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff88809622f000: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
                                              ^
 ffff88809622f080: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88809622f100: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
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