Messages in this thread | | | Date | Tue, 7 Jun 2011 14:54:14 +0300 | Subject | Re: [PATCH] slob/lockdep: Fix gfp flags passed to lockdep | From | Pekka Enberg <> |
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On Tue, Jun 7, 2011 at 2:18 PM, Steven Rostedt <rostedt@goodmis.org> wrote: > > Doing a ktest.pl randconfig, I stumbled across the following bug > on boot up: > > ------------[ cut here ]------------ > WARNING: at /home/rostedt/work/autotest/nobackup/linux-test.git/kernel/lockdep.c:2649 lockdep_trace_alloc+0xed/0x100() > Hardware name: > Modules linked in: > Pid: 0, comm: swapper Not tainted 3.0.0-rc1-test-00054-g1d68b67 #1 > Call Trace: > [<ffffffff810626ad>] warn_slowpath_common+0xad/0xf0 > [<ffffffff8106270a>] warn_slowpath_null+0x1a/0x20 > [<ffffffff810b537d>] lockdep_trace_alloc+0xed/0x100 > [<ffffffff81182fb0>] __kmalloc_node+0x30/0x2f0 > [<ffffffff81153eda>] pcpu_mem_alloc+0x13a/0x180 > [<ffffffff82be022c>] percpu_init_late+0x48/0xc2 > [<ffffffff82bd630c>] ? mem_init+0xd8/0xe3 > [<ffffffff82bbcc73>] start_kernel+0x1c2/0x449 > [<ffffffff82bbc35c>] x86_64_start_reservations+0x163/0x167 > [<ffffffff82bbc493>] x86_64_start_kernel+0x133/0x142^M > ---[ end trace a7919e7f17c0a725 ]--- > > Then I ran a ktest.pl config_bisect and it came up with this config > as the problem: > > CONFIG_SLOB > > Looking at what is different between SLOB and SLAB and SLUB, I found > that the gfp flags are masked against gfp_allowed_mask in > SLAB and SLUB, but not SLOB. > > On boot up, interrupts are disabled and lockdep will warn if some flags > are set in gfp and interrupts are disabled. But these flags are masked > off with the gfp_allowed_mask during boot. Because SLOB does not > mask the flags against gfp_allowed_mask it triggers the warn on. > > Adding this mask fixes the bug. I also found that kmem_cache_alloc_node() > was missing both the mask and the lockdep check, and that was added too. > > Cc: Matt Mackall <mpm@selenic.com> > Cc: Paul Mundt <lethal@linux-sh.org> > Cc: Nick Piggin <npiggin@kernel.dk> > Signed-off-by: Steven Rostedt <rostedt@goodmis.org> > > diff --git a/mm/slob.c b/mm/slob.c > index 46e0aee..0ae8818 100644 > --- a/mm/slob.c > +++ b/mm/slob.c > @@ -482,6 +482,8 @@ void *__kmalloc_node(size_t size, gfp_t gfp, int node) > int align = max(ARCH_KMALLOC_MINALIGN, ARCH_SLAB_MINALIGN); > void *ret; > > + gfp &= gfp_allowed_mask; > + > lockdep_trace_alloc(gfp); > > if (size < PAGE_SIZE - align) { > @@ -608,6 +610,10 @@ void *kmem_cache_alloc_node(struct kmem_cache *c, gfp_t flags, int node) > { > void *b; > > + flags &= gfp_allowed_mask; > + > + lockdep_trace_alloc(flags); > + > if (c->size < PAGE_SIZE) { > b = slob_alloc(c->size, flags, c->align, node); > trace_kmem_cache_alloc_node(_RET_IP_, b, c->size,
Matt, any objections to merging this? -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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