CVE-2024-42315 Information

Description

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.

Reference

https://git.kernel.org/stable/c/a7ac198f8dba791e3144c4da48a5a9b95773ee4b https://git.kernel.org/stable/c/1d1970493c289e3f44b9ec847ed26a5dbdf56a62 https://git.kernel.org/stable/c/89fc548767a2155231128cb98726d6d2ea1256c9