The kvmalloc function fails with a warning if the size is larger than INT_MAX. Linus said that there should be limits that prevent this warning from being hit. This commit adds the limits to the dm-stats subsystem.
Signed-off-by: Mikulas Patocka <[email protected]> --- drivers/md/dm-stats.c | 9 +++++++++ 1 file changed, 9 insertions(+) Index: linux-2.6/drivers/md/dm-stats.c =================================================================== --- linux-2.6.orig/drivers/md/dm-stats.c 2024-01-09 11:50:31.000000000 +0100 +++ linux-2.6/drivers/md/dm-stats.c 2024-01-09 11:57:10.000000000 +0100 @@ -66,6 +66,9 @@ struct dm_stats_last_position { unsigned int last_rw; }; +#define DM_STAT_MAX_ENTRIES 8388608 +#define DM_STAT_MAX_HISTOGRAM_ENTRIES 134217728 + /* * A typo on the command line could possibly make the kernel run out of memory * and crash. To prevent the crash we account all used memory. We fail if we @@ -285,6 +288,9 @@ static int dm_stats_create(struct dm_sta if (n_entries != (size_t)n_entries || !(size_t)(n_entries + 1)) return -EOVERFLOW; + if (n_entries > DM_STAT_MAX_ENTRIES) + return -EOVERFLOW; + shared_alloc_size = struct_size(s, stat_shared, n_entries); if ((shared_alloc_size - sizeof(struct dm_stat)) / sizeof(struct dm_stat_shared) != n_entries) return -EOVERFLOW; @@ -297,6 +303,9 @@ static int dm_stats_create(struct dm_sta if (histogram_alloc_size / (n_histogram_entries + 1) != (size_t)n_entries * sizeof(unsigned long long)) return -EOVERFLOW; + if ((n_histogram_entries + 1) * (size_t)n_entries > DM_STAT_MAX_HISTOGRAM_ENTRIES) + return -EOVERFLOW; + if (!check_shared_memory(shared_alloc_size + histogram_alloc_size + num_possible_cpus() * (percpu_alloc_size + histogram_alloc_size))) return -ENOMEM;
