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* [PATCH] powerpc/tm: Limit TM code inside PPC_TRANSACTIONAL_MEM
@ 2019-01-09 13:16 Breno Leitao
  2019-01-14 10:12 ` Michael Ellerman
  2019-01-16 13:35 ` [PATCH] " Sasha Levin
  0 siblings, 2 replies; 3+ messages in thread
From: Breno Leitao @ 2019-01-09 13:16 UTC (permalink / raw)
  To: linuxppc-dev; +Cc: Breno Leitao, mikey, stable, gregkh

Commit e1c3743e1a20 ("powerpc/tm: Set MSR[TS] just prior to recheckpoint")
moved a code block around and this block uses a 'msr' variable outside of
the CONFIG_PPC_TRANSACTIONAL_MEM, however the 'msr' variable is declared
inside a CONFIG_PPC_TRANSACTIONAL_MEM block, causing a possible error when
CONFIG_PPC_TRANSACTION_MEM is not defined.

	error: 'msr' undeclared (first use in this function)

This is not causing a compilation error in the mainline kernel, because
'msr' is being used as an argument of MSR_TM_ACTIVE(), which is defined as
the following when CONFIG_PPC_TRANSACTIONAL_MEM is *not* set:

	#define MSR_TM_ACTIVE(x) 0

This patch just fixes this issue avoiding the 'msr' variable usage outside
the CONFIG_PPC_TRANSACTIONAL_MEM block, avoiding trusting in the
MSR_TM_ACTIVE() definition.

Cc: stable@vger.kernel.org
Reported-by: Christoph Biedl <linux-kernel.bfrz@manchmal.in-ulm.de>
Fixes: e1c3743e1a20 ("powerpc/tm: Set MSR[TS] just prior to recheckpoint")
Signed-off-by: Breno Leitao <leitao@debian.org>
---

NB: Since stable kernels didn't cherry picked 5c784c8414fba ('powerpc/tm:
Remove msr_tm_active()), MSR_TM_ACTIVE() is not defined as 0 for
CONFIG_PPC_TRANSACTIONAL_MEM=n case, thus triggering the compilation error
above.

Tested against stable kernel 4.19.13-rc2 and problem is now fixed when
CONFIG_PPC_TRANSACTIONAL_MEM=n

 arch/powerpc/kernel/signal_64.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/arch/powerpc/kernel/signal_64.c b/arch/powerpc/kernel/signal_64.c
index daa28cb72272..8fe698162ab9 100644
--- a/arch/powerpc/kernel/signal_64.c
+++ b/arch/powerpc/kernel/signal_64.c
@@ -739,11 +739,12 @@ SYSCALL_DEFINE0(rt_sigreturn)
 		if (restore_tm_sigcontexts(current, &uc->uc_mcontext,
 					   &uc_transact->uc_mcontext))
 			goto badframe;
-	}
+	} else
 #endif
-	/* Fall through, for non-TM restore */
-	if (!MSR_TM_ACTIVE(msr)) {
+	{
 		/*
+		 * Fall through, for non-TM restore
+		 *
 		 * Unset MSR[TS] on the thread regs since MSR from user
 		 * context does not have MSR active, and recheckpoint was
 		 * not called since restore_tm_sigcontexts() was not called
-- 
2.19.0


^ permalink raw reply	[flat|nested] 3+ messages in thread

* Re: powerpc/tm: Limit TM code inside PPC_TRANSACTIONAL_MEM
  2019-01-09 13:16 [PATCH] powerpc/tm: Limit TM code inside PPC_TRANSACTIONAL_MEM Breno Leitao
@ 2019-01-14 10:12 ` Michael Ellerman
  2019-01-16 13:35 ` [PATCH] " Sasha Levin
  1 sibling, 0 replies; 3+ messages in thread
From: Michael Ellerman @ 2019-01-14 10:12 UTC (permalink / raw)
  To: Breno Leitao, linuxppc-dev; +Cc: Breno Leitao, gregkh, mikey, stable

On Wed, 2019-01-09 at 13:16:45 UTC, Breno Leitao wrote:
> Commit e1c3743e1a20 ("powerpc/tm: Set MSR[TS] just prior to recheckpoint")
> moved a code block around and this block uses a 'msr' variable outside of
> the CONFIG_PPC_TRANSACTIONAL_MEM, however the 'msr' variable is declared
> inside a CONFIG_PPC_TRANSACTIONAL_MEM block, causing a possible error when
> CONFIG_PPC_TRANSACTION_MEM is not defined.
> 
> 	error: 'msr' undeclared (first use in this function)
> 
> This is not causing a compilation error in the mainline kernel, because
> 'msr' is being used as an argument of MSR_TM_ACTIVE(), which is defined as
> the following when CONFIG_PPC_TRANSACTIONAL_MEM is *not* set:
> 
> 	#define MSR_TM_ACTIVE(x) 0
> 
> This patch just fixes this issue avoiding the 'msr' variable usage outside
> the CONFIG_PPC_TRANSACTIONAL_MEM block, avoiding trusting in the
> MSR_TM_ACTIVE() definition.
> 
> Cc: stable@vger.kernel.org
> Reported-by: Christoph Biedl <linux-kernel.bfrz@manchmal.in-ulm.de>
> Fixes: e1c3743e1a20 ("powerpc/tm: Set MSR[TS] just prior to recheckpoint")
> Signed-off-by: Breno Leitao <leitao@debian.org>

Applied to powerpc fixes, thanks.

https://git.kernel.org/powerpc/c/897bc3df8c5aebb54c32d831f917592e

cheers

^ permalink raw reply	[flat|nested] 3+ messages in thread

* Re: [PATCH] powerpc/tm: Limit TM code inside PPC_TRANSACTIONAL_MEM
  2019-01-09 13:16 [PATCH] powerpc/tm: Limit TM code inside PPC_TRANSACTIONAL_MEM Breno Leitao
  2019-01-14 10:12 ` Michael Ellerman
@ 2019-01-16 13:35 ` " Sasha Levin
  1 sibling, 0 replies; 3+ messages in thread
From: Sasha Levin @ 2019-01-16 13:35 UTC (permalink / raw)
  To: Sasha Levin; +Cc: , mikey, stable, gregkh

Hi,

[This is an automated email]

This commit has been processed because it contains a "Fixes:" tag,
fixing commit: e1c3743e1a20 powerpc/tm: Set MSR[TS] just prior to recheckpoint.

The bot has tested the following trees: v4.20.2, v4.19.15, v4.14.93, v4.9.150.

v4.20.2: Failed to apply! Possible dependencies:
    Unable to calculate

v4.19.15: Failed to apply! Possible dependencies:
    Unable to calculate

v4.14.93: Failed to apply! Possible dependencies:
    0d60619e1c0c ("powerpc: Add missing prototype for sys_debug_setcontext()")
    67b464a89c21 ("powerpc/32: Mark both tmp variables as unused")
    6f5b9f018f4c ("powerpc/tm: Unset MSR[TS] if not recheckpointing")
    b53875c4b4f2 ("powerpc: Add missing prototypes for sys_sigreturn() & sys_rt_sigreturn()")
    bf7fb32dd5fc ("powerpc: Add missing prototypes for ppc_select() & ppc_fadvise64_64()")
    f3675644e172 ("powerpc/syscalls: signal_{32, 64} - switch to SYSCALL_DEFINE")

v4.9.150: Failed to apply! Possible dependencies:
    0d60619e1c0c ("powerpc: Add missing prototype for sys_debug_setcontext()")
    67b464a89c21 ("powerpc/32: Mark both tmp variables as unused")
    6f5b9f018f4c ("powerpc/tm: Unset MSR[TS] if not recheckpointing")
    b53875c4b4f2 ("powerpc: Add missing prototypes for sys_sigreturn() & sys_rt_sigreturn()")
    bf7fb32dd5fc ("powerpc: Add missing prototypes for ppc_select() & ppc_fadvise64_64()")
    f3675644e172 ("powerpc/syscalls: signal_{32, 64} - switch to SYSCALL_DEFINE")


How should we proceed with this patch?

--
Thanks,
Sasha

^ permalink raw reply	[flat|nested] 3+ messages in thread

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Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed)
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2019-01-09 13:16 [PATCH] powerpc/tm: Limit TM code inside PPC_TRANSACTIONAL_MEM Breno Leitao
2019-01-14 10:12 ` Michael Ellerman
2019-01-16 13:35 ` [PATCH] " Sasha Levin

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