From 5256426247837feb8703625bda7fcfc824af04cf Mon Sep 17 00:00:00 2001 From: Christophe Leroy Date: Fri, 23 Apr 2021 13:52:10 +0000 Subject: [PATCH] powerpc/signal32: Fix erroneous SIGSEGV on RT signal return Return of user_read_access_begin() is tested the wrong way, leading to a SIGSEGV when the user address is valid and likely an Oops when the user address is bad. Fix the test. Fixes: 887f3ceb51cd ("powerpc/signal32: Convert do_setcontext[_tm]() to user access block") Signed-off-by: Christophe Leroy Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/a29aadc54c93bcbf069a83615fa102ca0f59c3ae.1619185912.git.christophe.leroy@csgroup.eu --- arch/powerpc/kernel/signal_32.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/arch/powerpc/kernel/signal_32.c b/arch/powerpc/kernel/signal_32.c index 94442af383e1..915ea2a457a0 100644 --- a/arch/powerpc/kernel/signal_32.c +++ b/arch/powerpc/kernel/signal_32.c @@ -971,7 +971,7 @@ static int do_setcontext(struct ucontext __user *ucp, struct pt_regs *regs, int sigset_t set; struct mcontext __user *mcp; - if (user_read_access_begin(ucp, sizeof(*ucp))) + if (!user_read_access_begin(ucp, sizeof(*ucp))) return -EFAULT; unsafe_get_sigset_t(&set, &ucp->uc_sigmask, failed); @@ -1009,7 +1009,7 @@ static int do_setcontext_tm(struct ucontext __user *ucp, u32 cmcp; u32 tm_cmcp; - if (user_read_access_begin(ucp, sizeof(*ucp))) + if (!user_read_access_begin(ucp, sizeof(*ucp))) return -EFAULT; unsafe_get_sigset_t(&set, &ucp->uc_sigmask, failed); -- 2.11.0