From mboxrd@z Thu Jan 1 00:00:00 1970 Subject: Re: [BUG] SLOB's krealloc() seems bust From: Peter Zijlstra In-Reply-To: <48EB6D2C.30806@linux-foundation.org> References: <1223387841.26330.36.camel@lappy.programming.kicks-ass.net> <48EB6D2C.30806@linux-foundation.org> Content-Type: text/plain Date: Tue, 07 Oct 2008 16:13:08 +0200 Message-Id: <1223388788.26330.38.camel@lappy.programming.kicks-ass.net> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: Christoph Lameter Cc: Matt Mackall , linux-mm , Nick Piggin , Linus Torvalds , Ingo Molnar , linux-kernel List-ID: On Tue, 2008-10-07 at 09:07 -0500, Christoph Lameter wrote: > > Which basically shows us that the content of the pcpu_size[] array got > > corrupted after the krealloc() call in split_block(). > > > > Which made me look at which slab allocator I had selected, which turned > > out to be SLOB (from testing the network swap stuff). > > krealloc() is in generic core code (mm/util.c) and is the same for all allocators. Joy :/ > krealloc uses ksize() which is somewhat dicey for SLOB because it only works > on kmalloc'ed memory. Is the krealloc used on memory allocated with kmalloc()? > Slob's ksize could use a BUG_ON for the case in which ksize() is used on > kmem_cache_alloc'd memory. kernel/module.c: perpcu_modinit() reads: pcpu_size = kmalloc(sizeof(pcpu_size[0]) * pcpu_num_allocated, GFP_KERNEL); kernel/module.c: split_block() reads: new = krealloc(pcpu_size, sizeof(new[0])*pcpu_num_allocated*2, GFP_KERNEL); -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org