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(-)
--- 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(); }