Hi Will, On 26.01.2016 17:59, Will Deacon wrote: > 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; > Yes I'm fine with that, Thanks! Mika -- 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>