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BUG: KASAN: slab-out-of-bounds in squashfs_get_id+0x1ae/0x1d0 fs/squashfs/id.c:38
Read of size 8 at addr ffff888012ad0f50 by task syz-executor.2/8638

CPU: 0 PID: 8638 Comm: syz-executor.2 Not tainted 5.9.0-next-20201016-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+0x198/0x1fb lib/dump_stack.c:118
 print_address_description.constprop.0.cold+0xae/0x497 mm/kasan/report.c:385
 __kasan_report mm/kasan/report.c:545 [inline]
 kasan_report.cold+0x1f/0x37 mm/kasan/report.c:562
 squashfs_get_id+0x1ae/0x1d0 fs/squashfs/id.c:38
 squashfs_new_inode fs/squashfs/inode.c:51 [inline]
 squashfs_read_inode+0x197/0x1940 fs/squashfs/inode.c:120
 squashfs_fill_super+0x1079/0x1ed0 fs/squashfs/super.c:310
 get_tree_bdev+0x421/0x740 fs/super.c:1344
 vfs_get_tree+0x89/0x2f0 fs/super.c:1549
 do_new_mount fs/namespace.c:2896 [inline]
 path_mount+0x12ae/0x1e70 fs/namespace.c:3227
 do_mount fs/namespace.c:3240 [inline]
 __do_sys_mount fs/namespace.c:3448 [inline]
 __se_sys_mount fs/namespace.c:3425 [inline]
 __x64_sys_mount+0x27f/0x300 fs/namespace.c:3425
 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x4608aa
Code: b8 a6 00 00 00 0f 05 48 3d 01 f0 ff ff 0f 83 ad 89 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 8a 89 fb ff c3 66 0f 1f 84 00 00 00 00 00
RSP: 002b:00007f0b907c7a88 EFLAGS: 00000202 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007f0b907c7b20 RCX: 00000000004608aa
RDX: 0000000020000000 RSI: 0000000020000100 RDI: 00007f0b907c7ae0
RBP: 00007f0b907c7ae0 R08: 00007f0b907c7b20 R09: 0000000020000000
R10: 0000000000000000 R11: 0000000000000202 R12: 0000000020000000
R13: 0000000020000100 R14: 0000000020000200 R15: 0000000020010200

Allocated by task 6869:
 kasan_save_stack+0x1b/0x40 mm/kasan/common.c:48
 kasan_set_track mm/kasan/common.c:56 [inline]
 __kasan_kmalloc.constprop.0+0xbf/0xd0 mm/kasan/common.c:461
 __do_kmalloc mm/slab.c:3657 [inline]
 __kmalloc_track_caller+0x279/0x4d0 mm/slab.c:3672
 kstrdup+0x36/0x70 mm/util.c:60
 kstrdup_const+0x53/0x80 mm/util.c:83
 __kernfs_new_node+0x9d/0x8b0 fs/kernfs/dir.c:623
 kernfs_new_node fs/kernfs/dir.c:689 [inline]
 kernfs_create_dir_ns+0x9c/0x220 fs/kernfs/dir.c:1026
 sysfs_create_dir_ns+0x127/0x290 fs/sysfs/dir.c:59
 create_dir lib/kobject.c:89 [inline]
 kobject_add_internal+0x2c3/0x940 lib/kobject.c:255
 kobject_add_varg lib/kobject.c:390 [inline]
 kobject_init_and_add+0x101/0x160 lib/kobject.c:473
 rx_queue_add_kobject net/core/net-sysfs.c:969 [inline]
 net_rx_queue_update_kobjects+0x1b7/0x450 net/core/net-sysfs.c:1020
 register_queue_kobjects net/core/net-sysfs.c:1654 [inline]
 netdev_register_kobject+0x271/0x3b0 net/core/net-sysfs.c:1902
 register_netdevice+0xd6b/0x1630 net/core/dev.c:9964
 nsim_create+0x245/0x2f0 drivers/net/netdevsim/netdev.c:317
 __nsim_dev_port_add+0x270/0x4c0 drivers/net/netdevsim/dev.c:935
 nsim_dev_port_add_all drivers/net/netdevsim/dev.c:984 [inline]
 nsim_dev_probe+0xc0a/0x1030 drivers/net/netdevsim/dev.c:1113
 really_probe+0x282/0x9f0 drivers/base/dd.c:555
 driver_probe_device+0xfe/0x1d0 drivers/base/dd.c:739
 __device_attach_driver+0x1c2/0x220 drivers/base/dd.c:845
 bus_for_each_drv+0x15f/0x1e0 drivers/base/bus.c:431
 __device_attach+0x228/0x470 drivers/base/dd.c:913
 bus_probe_device+0x1e4/0x290 drivers/base/bus.c:491
 device_add+0xb17/0x1c40 drivers/base/core.c:2938
 nsim_bus_dev_new drivers/net/netdevsim/bus.c:336 [inline]
 new_device_store+0x374/0x5c0 drivers/net/netdevsim/bus.c:215
 bus_attr_store+0x72/0xa0 drivers/base/bus.c:122
 sysfs_kf_write+0x110/0x160 fs/sysfs/file.c:139
 kernfs_fop_write+0x268/0x490 fs/kernfs/file.c:315
 vfs_write+0x28e/0x700 fs/read_write.c:603
 ksys_write+0x12d/0x250 fs/read_write.c:658
 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

The buggy address belongs to the object at ffff888012ad0f40
 which belongs to the cache kmalloc-32 of size 32
The buggy address is located 16 bytes inside of
 32-byte region [ffff888012ad0f40, ffff888012ad0f60)
The buggy address belongs to the page:
page:00000000fdeafef0 refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff888012ad0fc1 pfn:0x12ad0
flags: 0xfffe0000000200(slab)
raw: 00fffe0000000200 ffffea00003e7588 ffffea00005fab88 ffff88800ec40100
raw: ffff888012ad0fc1 ffff888012ad0000 000000010000003e 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff888012ad0e00: 00 00 00 00 fc fc fc fc 00 00 00 00 fc fc fc fc
 ffff888012ad0e80: 00 fc fc fc fc fc fc fc 05 fc fc fc fc fc fc fc
>ffff888012ad0f00: 06 fc fc fc fc fc fc fc 05 fc fc fc fc fc fc fc
                                                 ^
 ffff888012ad0f80: fa fb fb fb fc fc fc fc fc fc fc fc fc fc fc fc
 ffff888012ad1000: 00 fc fc fc fc fc fc fc fa fb fb fb fc fc fc fc
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