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 <mpatocka@xxxxxxxxxx>
---
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;
