In the Linux kernel, the following vulnerability has been resolved:

exfat: fix potential deadlock on __exfat_get_dentry_set

When accessing a file with more entries than ES_MAX_ENTRY_NUM, the bh-array
is allocated in __exfat_get_entry_set. The problem is that the bh-array is
allocated with GFP_KERNEL. It does not make sense. In the following cases,
a deadlock for sbi->s_lock between the two processes may occur.

       CPU0                CPU1
       ----                ----
  kswapd
   balance_pgdat
    lock(fs_reclaim)
                      exfat_iterate
                       lock(&sbi->s_lock)
                       exfat_readdir
                        exfat_get_uniname_from_ext_entry
                         exfat_get_dentry_set
                          __exfat_get_dentry_set
                           kmalloc_array
                            ...
                            lock(fs_reclaim)
    ...
    evict
     exfat_evict_inode
      lock(&sbi->s_lock)

To fix this, let's allocate bh-array with GFP_NOFS.

kernel.org https://git.kernel.org/stable/c/1d1970493c289e3f44b9ec847ed26a5dbdf56a62 [No types assigned]

kernel.org https://git.kernel.org/stable/c/89fc548767a2155231128cb98726d6d2ea1256c9 [No types assigned]

kernel.org https://git.kernel.org/stable/c/a7ac198f8dba791e3144c4da48a5a9b95773ee4b [No types assigned]