======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Not tainted
------------------------------------------------------
syz.3.6901/30656 is trying to acquire lock:
ffffffff8fc13b08 (gadget_subsys.su_mutex){+.+.}-{4:4}, at: uvcg_extension_b_num_controls_show+0x6f/0x130

but task is already holding lock:
ffff88810e57a270 (&p->frag_sem){++++}-{4:4}, at: configfs_read_iter+0x1cc/0x620

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #4 (&p->frag_sem){++++}-{4:4}:
       down_write_killable+0xa6/0x240
       configfs_rmdir+0x3b0/0x950
       vfs_rmdir+0x3e6/0x6a0
       filename_rmdir+0x292/0x520
       __se_sys_rmdir+0x2e/0x140
       do_syscall_64+0x166/0x520
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #3 (&sb->s_type->i_mutex_key#35){++++}-{4:4}:
       down_write+0x96/0x200
       configfs_depend_item_unlocked+0x153/0x420
       usbg_make_tpg+0x1e0/0x550
       target_fabric_make_tpg+0xa8/0x6d0
       configfs_mkdir+0x4f6/0x9e0
       vfs_mkdir+0x40c/0x620
       filename_mkdirat+0x285/0x510
       __se_sys_mkdirat+0x35/0x150
       do_syscall_64+0x166/0x520
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #2 (tpg_instances_lock){+.+.}-{4:4}:
       __mutex_lock+0x19d/0x1550
       tcm_alloc_inst+0x65/0x1a0
       usb_get_function_instance+0xe3/0x2f0
       function_make+0x127/0x360
       configfs_mkdir+0x4f6/0x9e0
       vfs_mkdir+0x40c/0x620
       filename_mkdirat+0x285/0x510
       __se_sys_mkdirat+0x35/0x150
       do_syscall_64+0x166/0x520
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #1 (func_lock){+.+.}-{4:4}:
       __mutex_lock+0x19d/0x1550
       usb_get_function_instance+0x2e/0x2f0
       function_make+0x127/0x360
       configfs_mkdir+0x4f6/0x9e0
       vfs_mkdir+0x40c/0x620
       filename_mkdirat+0x285/0x510
       __se_sys_mkdirat+0x35/0x150
       do_syscall_64+0x166/0x520
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #0 (gadget_subsys.su_mutex){+.+.}-{4:4}:
       __lock_acquire+0x164c/0x2de0
       lock_acquire+0x115/0x350
       __mutex_lock+0x19d/0x1550
       uvcg_extension_b_num_controls_show+0x6f/0x130
       configfs_read_iter+0x2b7/0x620
       __kernel_read+0x4ca/0x960
       integrity_kernel_read+0x89/0xd0
       ima_calc_file_hash+0x451/0x890
       ima_collect_measurement+0x51b/0xa00
       process_measurement+0x1272/0x1c10
       ima_file_check+0xe1/0x130
       security_file_post_open+0xb3/0x260
       path_openat+0x1485/0x1d60
       do_file_open+0x23e/0x4a0
       do_sys_openat2+0x115/0x200
       __x64_sys_openat+0x138/0x170
       do_syscall_64+0x166/0x520
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

other info that might help us debug this:

Chain exists of:
  gadget_subsys.su_mutex --> &sb->s_type->i_mutex_key#35 --> &p->frag_sem

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  rlock(&p->frag_sem);
                               lock(&sb->s_type->i_mutex_key#35);
                               lock(&p->frag_sem);
  lock(gadget_subsys.su_mutex);

 *** DEADLOCK ***

locks held by syz.3.6901/30656: 3, last CPU#0:
 #0: ffff88810e6ca168 (&ima_iint_mutex_key[depth]){+.+.}-{4:4}, at: process_measurement+0x7d0/0x1c10
 #1: ffff88810be88880 (&buffer->mutex#2){+.+.}-{4:4}, at: configfs_read_iter+0x70/0x620
 #2: ffff88810e57a270 (&p->frag_sem){++++}-{4:4}, at: configfs_read_iter+0x1cc/0x620

stack backtrace:
CPU: 0 UID: 0 PID: 30656 Comm: syz.3.6901 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150
 print_circular_bug+0x2e2/0x300
 check_noncircular+0x12f/0x150
 __lock_acquire+0x164c/0x2de0
 lock_acquire+0x115/0x350
 __mutex_lock+0x19d/0x1550
 uvcg_extension_b_num_controls_show+0x6f/0x130
 configfs_read_iter+0x2b7/0x620
 __kernel_read+0x4ca/0x960
 integrity_kernel_read+0x89/0xd0
 ima_calc_file_hash+0x451/0x890
 ima_collect_measurement+0x51b/0xa00
 process_measurement+0x1272/0x1c10
 ima_file_check+0xe1/0x130
 security_file_post_open+0xb3/0x260
 path_openat+0x1485/0x1d60
 do_file_open+0x23e/0x4a0
 do_sys_openat2+0x115/0x200
 __x64_sys_openat+0x138/0x170
 do_syscall_64+0x166/0x520
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f457e79e159
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f457f5d1028 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007f457ea25fa0 RCX: 00007f457e79e159
RDX: 0000000000000001 RSI: 0000200000000200 RDI: ffffffffffffff9c
RBP: 00007f457e83506b R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f457ea26038 R14: 00007f457ea25fa0 R15: 00007ffd4b1a4928
 </TASK>
