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riscv: Correctly free relocation hashtable on error

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When there is not enough allocatable memory for the relocation
hashtable, module loading should exit gracefully. Previously, this was
attempted to be accomplished by checking if an unsigned number is less
than zero which does not work. Instead have the caller check if the
hashtable was correctly allocated and add a comment explaining that
hashtable_bits that is 0 is valid.

Signed-off-by: Charlie Jenkins <charlie@rivosinc.com>
Fixes: d8792a5734b0 ("riscv: Safely remove entries from relocation list")
Reported-by: kernel test robot <lkp@intel.com>
Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
Closes: https://lore.kernel.org/r/202312132019.iYGTwW0L-lkp@intel.com/
Reported-by: kernel test robot <lkp@intel.com>
Reported-by: Julia Lawall <julia.lawall@inria.fr>
Closes: https://lore.kernel.org/r/202312120044.wTI1Uyaa-lkp@intel.com/
Reviewed-by: Dan Carpenter <dan.carpenter@linaro.org>
Link: https://lore.kernel.org/r/20240104-module_loading_fix-v3-2-a71f8de6ce0f@rivosinc.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
This commit is contained in:
Charlie Jenkins 2024-01-04 11:42:48 -08:00 committed by Palmer Dabbelt
parent 78996eee79
commit 4b38b36bfb
No known key found for this signature in database
GPG Key ID: 2E1319F35FBB1889
1 changed files with 7 additions and 3 deletions
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10
arch/riscv/kernel/module.c
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@ -747,6 +747,10 @@ initialize_relocation_hashtable(unsigned int num_relocations,
{
/* Can safely assume that bits is not greater than sizeof(long) */
unsigned long hashtable_size = roundup_pow_of_two(num_relocations);
/*
* When hashtable_size == 1, hashtable_bits == 0.
* This is valid because the hashing algorithm returns 0 in this case.
*/
unsigned int hashtable_bits = ilog2(hashtable_size);
/*
@ -763,7 +767,7 @@ initialize_relocation_hashtable(unsigned int num_relocations,
sizeof(*relocation_hashtable),
GFP_KERNEL);
if (!*relocation_hashtable)
return -ENOMEM;
return 0;
__hash_init(*relocation_hashtable, hashtable_size);
@ -789,8 +793,8 @@ int apply_relocate_add(Elf_Shdr *sechdrs, const char *strtab,
hashtable_bits = initialize_relocation_hashtable(num_relocations,
&relocation_hashtable);
if (hashtable_bits < 0)
return hashtable_bits;
if (!relocation_hashtable)
return -ENOMEM;
INIT_LIST_HEAD(&used_buckets_list);