Christoph Lameter wrote: > I have booted such a configuration just fine. Please have a look at the > kernel config that I send or send me yours.
OK. Here are complete steps to reproduce using QEMU on CentOS 6.4. (1) Compile the kernel for x86_32 and run it on QEMU. $ cd /tmp/ $ wget -O - https://git.kernel.org/cgit/linux/kernel/git/next/linux-next.git/snapshot/next-20130426.tar.bz2 | tar -jxf - $ cd next-20130426/ $ wget -O .config http://I-love.SAKURA.ne.jp/tmp/config-3.9-rc8-next-20130422 $ make -sj2 CONFIG_FRAME_POINTER=y CONFIG_DEBUG_INFO=y $ /usr/libexec/qemu-kvm -no-kvm -cpu pentium3 -m 512 -nographic -kernel arch/x86/boot/bzImage -S -gdb tcp::1234 (2) Attach gdb to the QEMU process from another terminal and continue. $ gdb /tmp/next-20130426/vmlinux (gdb) target remote :1234 (gdb) c Press Ctrl-C after waiting for ten seconds. You will find that the kernel has panic()ed. If one of CONFIG_DEBUG_SLAB/CONFIG_DEBUG_SPINLOCK/CONFIG_DEBUG_PAGEALLOC is changed to n from the config above, the kernel boots fine. But the kernel triggers oops for very large kmalloc allocations. > > Here is a patch that restores the old behavior for SLAB > > > > Subject: slab: Return NULL for oversized allocations > > The inline path seems to have changed the SLAB behavior for very large > kmalloc allocations. This patch restores the old behavior. > > Signed-off-by: Christoph Lameter <c...@linux.com> > I don't think this patch is sufficient. There are functions (e.g. kstrdup()) which call variant functions (e.g. kmalloc_track_caller()). I think we need to check size at functions which determine index from size (e.g. kmalloc_slab()). > > Index: linux/include/linux/slab_def.h > =================================================================== > --- linux.orig/include/linux/slab_def.h 2013-05-02 15:02:45.864728115 > -0500 > +++ linux/include/linux/slab_def.h 2013-05-02 15:06:14.940474110 -0500 > @@ -126,6 +126,9 @@ static __always_inline void *kmalloc(siz > if (!size) > return ZERO_SIZE_PTR; > > + if (size >= KMALLOC_MAX_SIZE) > + return NULL; > + Why not (size > KMALLOC_MAX_SIZE) ? > i = kmalloc_index(size); > > #ifdef CONFIG_ZONE_DMA -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
