* [PATCH AUTOSEL 5.15 182/188] parisc: Avoid calling faulthandler_disabled() twice
[not found] <20220118023152.1948105-1-sashal@kernel.org>
@ 2022-01-18 2:31 ` Sasha Levin
0 siblings, 0 replies; only message in thread
From: Sasha Levin @ 2022-01-18 2:31 UTC (permalink / raw)
To: linux-kernel, stable
Cc: John David Anglin, Helge Deller, Sasha Levin, James.Bottomley,
svens, ebiederm, wangkefeng.wang, rmk+kernel, linux-parisc
From: John David Anglin <dave.anglin@bell.net>
[ Upstream commit 9e9d4b460f23bab61672eae397417d03917d116c ]
In handle_interruption(), we call faulthandler_disabled() to check whether the
fault handler is not disabled. If the fault handler is disabled, we immediately
call do_page_fault(). It then calls faulthandler_disabled(). If disabled,
do_page_fault() attempts to fixup the exception by jumping to no_context:
no_context:
if (!user_mode(regs) && fixup_exception(regs)) {
return;
}
parisc_terminate("Bad Address (null pointer deref?)", regs, code, address);
Apart from the error messages, the two blocks of code perform the same
function.
We can avoid two calls to faulthandler_disabled() by a simple revision
to the code in handle_interruption().
Note: I didn't try to fix the formatting of this code block.
Signed-off-by: John David Anglin <dave.anglin@bell.net>
Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
arch/parisc/kernel/traps.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/parisc/kernel/traps.c b/arch/parisc/kernel/traps.c
index 197cb8480350c..afe8b902a8fc4 100644
--- a/arch/parisc/kernel/traps.c
+++ b/arch/parisc/kernel/traps.c
@@ -784,7 +784,7 @@ void notrace handle_interruption(int code, struct pt_regs *regs)
* unless pagefault_disable() was called before.
*/
- if (fault_space == 0 && !faulthandler_disabled())
+ if (faulthandler_disabled() || fault_space == 0)
{
/* Clean up and return if in exception table. */
if (fixup_exception(regs))
--
2.34.1
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2022-01-18 2:31 ` [PATCH AUTOSEL 5.15 182/188] parisc: Avoid calling faulthandler_disabled() twice Sasha Levin
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