Hi Mika, On Tue, Jan 26, 2016 at 04:59:52PM +0200, mika.penttila@xxxxxxxxxxxx wrote: > From: Mika Penttilä <mika.penttila@xxxxxxxxxxxx> > > This makes the caller set_memory_xx() consistent with x86. > > arm64 part is rebased on 4.5.0-rc1 with Ard's patch > lkml.kernel.org/g/<1453125665-26627-1-git-send-email-ard.biesheuvel@xxxxxxxxxx> > applied. > > Signed-off-by: Mika Penttilä mika.penttila@xxxxxxxxxxxx > Reviewed-by: Laura Abbott <labbott@xxxxxxxxxx> > Acked-by: David Rientjes <rientjes@xxxxxxxxxx> > > --- > arch/arm/mm/pageattr.c | 3 +++ > arch/arm64/mm/pageattr.c | 3 +++ > 2 files changed, 6 insertions(+) > > diff --git a/arch/arm/mm/pageattr.c b/arch/arm/mm/pageattr.c > index cf30daf..d19b1ad 100644 > --- a/arch/arm/mm/pageattr.c > +++ b/arch/arm/mm/pageattr.c > @@ -49,6 +49,9 @@ static int change_memory_common(unsigned long addr, int numpages, > WARN_ON_ONCE(1); > } > > + if (!numpages) > + return 0; > + > if (start < MODULES_VADDR || start >= MODULES_END) > return -EINVAL; > > diff --git a/arch/arm64/mm/pageattr.c b/arch/arm64/mm/pageattr.c > index 1360a02..b582fc2 100644 > --- a/arch/arm64/mm/pageattr.c > +++ b/arch/arm64/mm/pageattr.c > @@ -53,6 +53,9 @@ static int change_memory_common(unsigned long addr, int numpages, > WARN_ON_ONCE(1); > } > > + if (!numpages) > + return 0; > + Thanks for this. I can reproduce the failure on my Juno board, so I'd like to queue this for 4.5 since it fixes a real issue. I've taken the liberty of rebasing the arm64 part to my fixes branch and writing a commit message. Does the patch below look ok to you? Will --->8 >From 57adec866c0440976c96a4b8f5b59fb411b1cacb Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Mika=20Penttil=C3=A4?= <mika.penttila@xxxxxxxxxxxx> Date: Tue, 26 Jan 2016 15:47:25 +0000 Subject: [PATCH] arm64: mm: avoid calling apply_to_page_range on empty range MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Calling apply_to_page_range with an empty range results in a BUG_ON from the core code. This can be triggered by trying to load the st_drv module with CONFIG_DEBUG_SET_MODULE_RONX enabled: kernel BUG at mm/memory.c:1874! Internal error: Oops - BUG: 0 [#1] PREEMPT SMP Modules linked in: CPU: 3 PID: 1764 Comm: insmod Not tainted 4.5.0-rc1+ #2 Hardware name: ARM Juno development board (r0) (DT) task: ffffffc9763b8000 ti: ffffffc975af8000 task.ti: ffffffc975af8000 PC is at apply_to_page_range+0x2cc/0x2d0 LR is at change_memory_common+0x80/0x108 This patch fixes the issue by making change_memory_common (called by the set_memory_* functions) a NOP when numpages == 0, therefore avoiding the erroneous call to apply_to_page_range and bringing us into line with x86 and s390. Cc: <stable@xxxxxxxxxxxxxxx> Reviewed-by: Laura Abbott <labbott@xxxxxxxxxx> Acked-by: David Rientjes <rientjes@xxxxxxxxxx> Signed-off-by: Mika Penttilä <mika.penttila@xxxxxxxxxxxx> Signed-off-by: Will Deacon <will.deacon@xxxxxxx> --- arch/arm64/mm/pageattr.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/arch/arm64/mm/pageattr.c b/arch/arm64/mm/pageattr.c index 3571c7309c5e..cf6240741134 100644 --- a/arch/arm64/mm/pageattr.c +++ b/arch/arm64/mm/pageattr.c @@ -57,6 +57,9 @@ static int change_memory_common(unsigned long addr, int numpages, if (end < MODULES_VADDR || end >= MODULES_END) return -EINVAL; + if (!numpages) + return 0; + data.set_mask = set_mask; data.clear_mask = clear_mask; -- 2.1.4 -- 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>