On Wed, 11 Nov 2015 12:41:08 -0800 Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> wrote: > On Wed, 11 Nov 2015 14:34:19 +0800 kbuild test robot <fengguang.wu@xxxxxxxxx> wrote: > > > tree: https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git master > > head: 2bba65ab5f9f1cebd21d95c410b96952851f58b3 > > commit: e191357c4c31d02eb30736a49327ef32407fab47 [12891/13017] slub: create new ___slab_alloc function that can be called with irqs disabled > > config: s390-allmodconfig (attached as .config) > > reproduce: > > wget https://git.kernel.org/cgit/linux/kernel/git/wfg/lkp-tests.git/plain/sbin/make.cross -O ~/bin/make.cross > > chmod +x ~/bin/make.cross > > git checkout e191357c4c31d02eb30736a49327ef32407fab47 > > # save the attached .config to linux build tree > > make.cross ARCH=s390 > > > > All warnings (new ones prefixed by >>): > > > > mm/slub.c: In function 'unfreeze_partials.isra.42': > > mm/slub.c:2019:1: warning: 'unfreeze_partials.isra.42' uses dynamic stack allocation > > } > > ^ > > mm/slub.c: In function 'get_partial_node.isra.43': > > mm/slub.c:1654:1: warning: 'get_partial_node.isra.43' uses dynamic stack allocation > > } > > ^ > > mm/slub.c: In function 'deactivate_slab': > > mm/slub.c:1951:1: warning: 'deactivate_slab' uses dynamic stack allocation > > } > > ^ > > mm/slub.c: In function '__slab_free': > > mm/slub.c:2696:1: warning: '__slab_free' uses dynamic stack allocation > > } > > ^ > > mm/slub.c: In function '___slab_alloc': > > >> mm/slub.c:2396:1: warning: '___slab_alloc' uses dynamic stack allocation > > } > > ^ > > This patch doesn't add any dynamic stack allocations. The fact that > slub.c already had a bunch of these warnings makes me suspect that it's > happening in one of the s390 headers? That looks like a false positive to me. I can not find any function that does a dynamic allocation and the generated code creates a stack frame with a constant size. A bit odd is the fact that the stack frame is create in two steps, e.g. deactivate_slab: a632: b9 04 00 ef lgr %r14,%r15 a636: a7 fb ff 50 aghi %r15,-176 # first 176 bytes a63a: b9 04 00 bf lgr %r11,%r15 a63e: e3 e0 f0 98 00 24 stg %r14,152(%r15) a644: e3 10 f0 98 00 04 lg %r1,152(%r15) a64a: a7 fb ff 30 aghi %r15,-208 # another 208 bytes a64e: e3 30 b0 e8 00 24 stg %r3,232(%r11) a654: e3 40 b0 d8 00 24 stg %r4,216(%r11) Strange. Andreas can you make something of this? -- blue skies, Martin. "Reality continues to ruin my life." - Calvin. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>