path: root/utils.c
diff options
authorDavid Sterba <>2015-02-27 19:37:24 +0100
committerDavid Sterba <>2015-06-11 01:10:10 +0200
commit6d7999d5b747283314c0f3833a3d9515f674a446 (patch)
tree5af8bb4c6219e6264f7b5ecb680d7b475c9a613f /utils.c
parent4ceffd0927360c83bec94606112b4e59cb7d2d73 (diff)
btrfs-progs: use less memory for pretty_size_mode buffers
Anand reports that the static buffers used for pertty size strings cause a stack overflow on SPARC. Zach proposed to change the printf format to wrap the number and the suffix into a macro. This would require to change all callsites of pretty_size* and is not very convienient to write. This patch replaces the per-call-site static buffers with a limited number for slots that would be used on each invokation of pretty_size and wrap around. The number of array slots shall be 10 for now, in current codebase there are no more than 2 calls to pretty_size in a single argument list. Reported-by: Anand Jain <> CC: Zach Brown <> Signed-off-by: David Sterba <>
Diffstat (limited to 'utils.c')
1 files changed, 18 insertions, 0 deletions
diff --git a/utils.c b/utils.c
index b4983812..e89707c7 100644
--- a/utils.c
+++ b/utils.c
@@ -1479,6 +1479,24 @@ out:
return ret;
+ * Note: this function uses a static per-thread buffer. Do not call this
+ * function more than 10 times within one argument list!
+ */
+const char *pretty_size_mode(u64 size, unsigned mode)
+ static __thread int ps_index = 0;
+ static __thread char ps_array[10][32];
+ char *ret;
+ ret = ps_array[ps_index];
+ ps_index++;
+ ps_index %= 10;
+ (void)pretty_size_snprintf(size, ret, 32, mode);
+ return ret;
static const char* unit_suffix_binary[] =
{ "B", "KiB", "MiB", "GiB", "TiB", "PiB", "EiB"};
static const char* unit_suffix_decimal[] =