From: Marc Dionne Date: Thu, 31 Oct 2024 10:55:34 +0000 (-0300) Subject: tools/mm: fix slabinfo crash when MAX_SLABS is exceeded X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=acb3bc729b542d2f9ed935fbc41b9f0c11056942;p=users%2Fjedix%2Flinux-maple.git tools/mm: fix slabinfo crash when MAX_SLABS is exceeded The number of slabs can easily exceed the hard coded MAX_SLABS in the slabinfo tool, causing it to overwrite memory and crash. Increase the value of MAX_SLABS, and check if that has been exceeded for each new slab, instead of at the end when it's already too late. Also move the check for MAX_ALIASES into the loop body. Link: https://lkml.kernel.org/r/20241031105534.565533-1-marc.c.dionne@gmail.com Signed-off-by: Marc Dionne Cc: Vlastimil Babka Signed-off-by: Andrew Morton --- diff --git a/tools/mm/slabinfo.c b/tools/mm/slabinfo.c index 04e9e6ba86ea..1433eff99feb 100644 --- a/tools/mm/slabinfo.c +++ b/tools/mm/slabinfo.c @@ -21,7 +21,7 @@ #include #include -#define MAX_SLABS 500 +#define MAX_SLABS 2000 #define MAX_ALIASES 500 #define MAX_NODES 1024 @@ -1228,6 +1228,8 @@ static void read_slab_dir(void) continue; switch (de->d_type) { case DT_LNK: + if (alias - aliasinfo == MAX_ALIASES) + fatal("Too many aliases\n"); alias->name = strdup(de->d_name); count = readlink(de->d_name, buffer, sizeof(buffer)-1); @@ -1242,6 +1244,8 @@ static void read_slab_dir(void) alias++; break; case DT_DIR: + if (slab - slabinfo == MAX_SLABS) + fatal("Too many slabs\n"); if (chdir(de->d_name)) fatal("Unable to access slab %s\n", slab->name); slab->name = strdup(de->d_name); @@ -1312,10 +1316,6 @@ static void read_slab_dir(void) slabs = slab - slabinfo; actual_slabs = slabs; aliases = alias - aliasinfo; - if (slabs > MAX_SLABS) - fatal("Too many slabs\n"); - if (aliases > MAX_ALIASES) - fatal("Too many aliases\n"); } static void output_slabs(void)