diff mbox series

[5.12,158/161] x86/fault: Dont send SIGSEGV twice on SEGV_PKUERR

Message ID 20210608175950.794678689@linuxfoundation.org
State New
Headers show
Series None | expand

Commit Message

Greg KH June 8, 2021, 6:28 p.m. UTC 
From: Jiashuo Liang <liangjs@pku.edu.cn>

commit 5405b42c2f08efe67b531799ba2fdb35bac93e70 upstream.

__bad_area_nosemaphore() calls both force_sig_pkuerr() and
force_sig_fault() when handling SEGV_PKUERR. This does not cause
problems because the second signal is filtered by the legacy_queue()
check in __send_signal() because in both cases, the signal is SIGSEGV,
the second one seeing that the first one is already pending.

This causes the kernel to do unnecessary work so send the signal only
once for SEGV_PKUERR.

 [ bp: Massage commit message. ]

Fixes: 9db812dbb29d ("signal/x86: Call force_sig_pkuerr from __bad_area_nosemaphore")
Suggested-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Jiashuo Liang <liangjs@pku.edu.cn>
Signed-off-by: Borislav Petkov <bp@suse.de>
Acked-by: "Eric W. Biederman" <ebiederm@xmission.com>
Link: https://lkml.kernel.org/r/20210601085203.40214-1-liangjs@pku.edu.cn
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 arch/x86/mm/fault.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)
diff mbox series

Patch

--- a/arch/x86/mm/fault.c
+++ b/arch/x86/mm/fault.c
@@ -836,8 +836,8 @@  __bad_area_nosemaphore(struct pt_regs *r
 
 	if (si_code == SEGV_PKUERR)
 		force_sig_pkuerr((void __user *)address, pkey);
-
-	force_sig_fault(SIGSEGV, si_code, (void __user *)address);
+	else
+		force_sig_fault(SIGSEGV, si_code, (void __user *)address);
 
 	local_irq_disable();
 }