From 7092e9b3bed1252c7d3f5812b9fb9d82375b73a6 Mon Sep 17 00:00:00 2001 From: Kartik Date: Tue, 17 Oct 2023 10:53:15 +0530 Subject: mm/util: Introduce kmemdup_array() Introduce kmemdup_array() API to duplicate `n` number of elements from a given array. This internally uses kmemdup to allocate and duplicate the `src` array. Signed-off-by: Kartik Acked-by: Kees Cook Signed-off-by: Thierry Reding --- mm/util.c | 17 +++++++++++++++++ 1 file changed, 17 insertions(+) (limited to 'mm/util.c') diff --git a/mm/util.c b/mm/util.c index 5a6a9802583b..5faf3adc6f43 100644 --- a/mm/util.c +++ b/mm/util.c @@ -135,6 +135,23 @@ void *kmemdup(const void *src, size_t len, gfp_t gfp) } EXPORT_SYMBOL(kmemdup); +/** + * kmemdup_array - duplicate a given array. + * + * @src: array to duplicate. + * @element_size: size of each element of array. + * @count: number of elements to duplicate from array. + * @gfp: GFP mask to use. + * + * Return: duplicated array of @src or %NULL in case of error, + * result is physically contiguous. Use kfree() to free. + */ +void *kmemdup_array(const void *src, size_t element_size, size_t count, gfp_t gfp) +{ + return kmemdup(src, size_mul(element_size, count), gfp); +} +EXPORT_SYMBOL(kmemdup_array); + /** * kvmemdup - duplicate region of memory * -- cgit v1.2.3 From f5eec03611d9352c8b19134ecd4742a6ebc45282 Mon Sep 17 00:00:00 2001 From: Matthew Cassell Date: Thu, 22 Feb 2024 19:46:17 +0000 Subject: mm/util.c: add byte count to __vm_enough_memory failure warning Commit 44b414c8715c5dcf53288 ("mm/util.c: add warning if __vm_enough_memory fails") adds debug information which gives the process id and executable name should __vm_enough_memory() fail. Adding the number of pages to the failure message would benefit application developers and system administrators in debugging overambitious memory requests by providing a point of reference to the amount of memory causing __vm_enough_memory() to fail. 1. Set appropriate kernel tunable to reach code path for failure message: # echo 2 > /proc/sys/vm/overcommit_memory 2. Test program to generate failure - requests 1 gibibyte per iteration: #include #include int main(int argc, char **argv) { for(;;) { if(malloc(1<<30) == NULL) break; printf("allocated 1 GiB\n"); } return 0; } 3. Output: Before: __vm_enough_memory: pid: 1218, comm: a.out, not enough memory for the allocation After: __vm_enough_memory: pid: 1137, comm: a.out, bytes: 1073741824, not enough memory for the allocation Link: https://lkml.kernel.org/r/20240222194617.1255-1-mcassell411@gmail.com Signed-off-by: Matthew Cassell Cc: David Hildenbrand Signed-off-by: Andrew Morton --- mm/util.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) (limited to 'mm/util.c') diff --git a/mm/util.c b/mm/util.c index 5a6a9802583b..6710efaf1802 100644 --- a/mm/util.c +++ b/mm/util.c @@ -942,6 +942,7 @@ EXPORT_SYMBOL_GPL(vm_memory_committed); int __vm_enough_memory(struct mm_struct *mm, long pages, int cap_sys_admin) { long allowed; + unsigned long bytes_failed; vm_acct_memory(pages); @@ -976,8 +977,9 @@ int __vm_enough_memory(struct mm_struct *mm, long pages, int cap_sys_admin) if (percpu_counter_read_positive(&vm_committed_as) < allowed) return 0; error: - pr_warn_ratelimited("%s: pid: %d, comm: %s, not enough memory for the allocation\n", - __func__, current->pid, current->comm); + bytes_failed = pages << PAGE_SHIFT; + pr_warn_ratelimited("%s: pid: %d, comm: %s, bytes: %lu not enough memory for the allocation\n", + __func__, current->pid, current->comm, bytes_failed); vm_unacct_memory(pages); return -ENOMEM; -- cgit v1.2.3