summaryrefslogtreecommitdiff
path: root/arch/powerpc
diff options
context:
space:
mode:
authorNaveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>2017-08-31 21:55:57 +0530
committerMichael Ellerman <mpe@ellerman.id.au>2017-11-13 10:53:05 +1100
commit46725b17f1c6c815a41429259b3f070c01e71bc1 (patch)
treed2535594629172daf8462e30df3937129dc10808 /arch/powerpc
parentdcdc46794b7bb76733d9792cca2f45871d66881f (diff)
powerpc/signal: Properly handle return value from uprobe_deny_signal()
When a uprobe is installed on an instruction that we currently do not emulate, we copy the instruction into a xol buffer and single step that instruction. If that instruction generates a fault, we abort the single stepping before invoking the signal handler. Once the signal handler is done, the uprobe trap is hit again since the instruction is retried and the process repeats. We use uprobe_deny_signal() to detect if the xol instruction triggered a signal. If so, we clear TIF_SIGPENDING and set TIF_UPROBE so that the signal is not handled until after the single stepping is aborted. In this case, uprobe_deny_signal() returns true and get_signal() ends up returning 0. However, in do_signal(), we are not looking at the return value, but depending on ksig.sig for further action, all with an uninitialized ksig that is not touched in this scenario. Fix the same by initializing ksig.sig to 0. Fixes: 129b69df9c90 ("powerpc: Use get_signal() signal_setup_done()") Cc: stable@vger.kernel.org # v3.17+ Reported-by: Anton Blanchard <anton@samba.org> Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Diffstat (limited to 'arch/powerpc')
-rw-r--r--arch/powerpc/kernel/signal.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/powerpc/kernel/signal.c b/arch/powerpc/kernel/signal.c
index e9436c5e1e09..3d7539b90010 100644
--- a/arch/powerpc/kernel/signal.c
+++ b/arch/powerpc/kernel/signal.c
@@ -103,7 +103,7 @@ static void check_syscall_restart(struct pt_regs *regs, struct k_sigaction *ka,
static void do_signal(struct task_struct *tsk)
{
sigset_t *oldset = sigmask_to_save();
- struct ksignal ksig;
+ struct ksignal ksig = { .sig = 0 };
int ret;
int is32 = is_32bit_task();