powerpc/tm: Limit TM code inside PPC_TRANSACTIONAL_MEM

Message ID 1547039805-7979-1-git-send-email-leitao@debian.org
State Accepted
Commit 897bc3df8c5aebb54c32d831f917592e873d0559
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Series
  • powerpc/tm: Limit TM code inside PPC_TRANSACTIONAL_MEM
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Context Check Description
snowpatch_ozlabs/checkpatch warning total: 0 errors, 0 warnings, 1 checks, 15 lines checked
snowpatch_ozlabs/build-pmac32 success build succeeded & removed 0 sparse warning(s)
snowpatch_ozlabs/build-ppc64e success build succeeded & removed 0 sparse warning(s)
snowpatch_ozlabs/build-ppc64be success build succeeded & removed 0 sparse warning(s)
snowpatch_ozlabs/build-ppc64le success build succeeded & removed 0 sparse warning(s)
snowpatch_ozlabs/apply_patch success next/apply_patch Successfully applied

Commit Message

Breno Leitao Jan. 9, 2019, 1:16 p.m.
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(-)

Comments

Sasha Levin Jan. 16, 2019, 1:35 p.m. | #1
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
Breno Leitao Jan. 17, 2019, 11:49 a.m. | #2
hi Sasha,

On 1/16/19 11:35 AM, Sasha Levin wrote:
> 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?

I understand that the commit that this patch fixes is not integrated into
stable tree.

I think it does not need to make stable at this moment, thus.

Thanks,
Breno
Sasha Levin Jan. 18, 2019, 2:51 p.m. | #3
On Thu, Jan 17, 2019 at 09:49:05AM -0200, Breno Leitao wrote:
>hi Sasha,
>
>On 1/16/19 11:35 AM, Sasha Levin wrote:
>> 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?
>
>I understand that the commit that this patch fixes is not integrated into
>stable tree.
>
>I think it does not need to make stable at this moment, thus.

The commit it fixes (e1c3743e1a20) exists in all 4.9+ stable trees as it
itself was tagged for stable.

--
Thanks,
Sasha

Patch

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