Warming up an ancient thread because the discussion seems to have just stalled at some point and I still have this patch bitrotting in patchwork. The original thread can be found at: http://www.linux-mips.org/archives/linux-mips/2012-03/msg00006.html http://www.linux-mips.org/archives/linux-mips/2012-03/msg00028.html On Wed, Mar 07, 2012 at 03:09:28PM +0200, Veli-Pekka Peltola wrote: > After commit de7d2b567d040e3b67fe7121945982f14343213d (mm/vmalloc.c: report > more vmalloc failures) users will get a warning if vmalloc_node_range() is > called with size 0. This happens if module's init size equals to 0. This > patch changes ARM, MIPS and x86 module_alloc() to return NULL before calling > vmalloc_node_range() that would also return NULL and print a warning. > > Signed-off-by: Veli-Pekka Peltola <veli-pekka.peltola@xxxxxxxxxxxx> > Cc: Russell King <linux@xxxxxxxxxxxxxxxx> > Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx> > Cc: Ingo Molnar <mingo@xxxxxxxxxx> > Cc: "H. Peter Anvin" <hpa@xxxxxxxxx> > Cc: x86@xxxxxxxxxx > --- > I found this with ARM but after checking out various implementations of > module_alloc() I thought it would be better to fix all at once. > > One way to replicate the warning: > compile kernel with CONFIG_KALLSYMS=n > insmod a module without init, I used usb-common.ko I didn't try to reproduce the issue but the code in question doesn't seem to have changed so the issue should still persist. Imho de7d2b567d040e3b67fe7121945982f14343213d [mm/vmalloc.c: report more vmalloc failures] is overly strict in that it also reports zero-sized allocations. I consider such allocations stupid but legitimiate and often better preferrable over having to scatter checks for zero size all over place. So maybe something like below patch? Thanks, Ralf --- Signed-off-by: Ralf Baechle <ralf@xxxxxxxxxxxxxx> mm/vmalloc.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/mm/vmalloc.c b/mm/vmalloc.c index d365724..e58ca10 100644 --- a/mm/vmalloc.c +++ b/mm/vmalloc.c @@ -1679,7 +1679,10 @@ void *__vmalloc_node_range(unsigned long size, unsigned long align, unsigned long real_size = size; size = PAGE_ALIGN(size); - if (!size || (size >> PAGE_SHIFT) > totalram_pages) + if (unlikely(!size)) + return NULL; + + if ((size >> PAGE_SHIFT) > totalram_pages) goto fail; area = __get_vm_area_node(size, align, VM_ALLOC | VM_UNLIST, @@ -1711,6 +1714,7 @@ fail: warn_alloc_failed(gfp_mask, 0, "vmalloc: allocation failure: %lu bytes\n", real_size); + return NULL; }
