Skip to contentSkip to conversation

FAILED: patch "[PATCH] ARM: 9109/1: oabi-compat: add epoll_pwait handler" failed to apply to 4.4-stable tree

PATCH [email protected] 2 participants 2 messages Sep 15, 2021

Subsystems (2)
Stable branch Arm (32-bit)
lore
Share & tools
lore

[email protected]

author maintainer
#0 lore raw

The patch below does not apply to the 4.4-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From b6e47f3c11c17965acb2a12001af3b1cd5658f37 Mon Sep 17 00:00:00 2001
From: Arnd Bergmann <[email protected]>
Date: Wed, 11 Aug 2021 08:30:20 +0100
Subject: [PATCH] ARM: 9109/1: oabi-compat: add epoll_pwait handler

The epoll_wait() syscall has a special version for OABI compat mode to convert the arguments to the EABI structure layout of the kernel. However, the later epoll_pwait() syscall was added in arch/arm in linux-2.6.32 without this conversion.

Use the same kind of handler for both.

Fixes 369842658a36 ("ARM: 5677/1: ARM support for TIF_RESTORE_SIGMASK/pselect6/ppoll/epoll_pwait")
Cc [email protected]
Reviewed-by Christoph Hellwig <[email protected]>
Signed-off-by Arnd Bergmann <[email protected]>
Signed-off-by Russell King (Oracle) <[email protected]>
arch/arm/kernel/sys_oabi-compat.c +35 -3
index 075a2e0ed2c1..443203fafb6b 100644
@@ -265,9 +265,8 @@ asmlinkage long sys_oabi_epoll_ctl(int epfd, int op, int fd,
 	return do_epoll_ctl(epfd, op, fd, &kernel, false);
 }
 
-asmlinkage long sys_oabi_epoll_wait(int epfd,
-				    struct oabi_epoll_event __user *events,
-				    int maxevents, int timeout)
+static long do_oabi_epoll_wait(int epfd, struct oabi_epoll_event __user *events,
+			       int maxevents, int timeout)
 {
 	struct epoll_event *kbuf;
 	struct oabi_epoll_event e;

@@ -314,6 +313,39 @@ asmlinkage long sys_oabi_epoll_wait(int epfd,
 }
 #endif
 
+SYSCALL_DEFINE4(oabi_epoll_wait, int, epfd,
+		struct oabi_epoll_event __user *, events,
+		int, maxevents, int, timeout)
+{
+	return do_oabi_epoll_wait(epfd, events, maxevents, timeout);
+}
+
+/*
+ * Implement the event wait interface for the eventpoll file. It is the kernel
+ * part of the user space epoll_pwait(2).
+ */
+SYSCALL_DEFINE6(oabi_epoll_pwait, int, epfd,
+		struct oabi_epoll_event __user *, events, int, maxevents,
+		int, timeout, const sigset_t __user *, sigmask,
+		size_t, sigsetsize)
+{
+	int error;
+
+	/*
+	 * If the caller wants a certain signal mask to be set during the wait,
+	 * we apply it here.
+	 */
+	error = set_user_sigmask(sigmask, sigsetsize);
+	if (error)
+		return error;
+
+	error = do_oabi_epoll_wait(epfd, events, maxevents, timeout);
+	restore_saved_sigmask_unless(error == -EINTR);
+
+	return error;
+}
+#endif
+
 struct oabi_sembuf {
 	unsigned short	sem_num;
 	short		sem_op;
arch/arm/tools/syscall.tbl +1 -1
index c5df1179fc5d..11d0b960b2c2 100644
@@ -360,7 +360,7 @@
 343	common	vmsplice		sys_vmsplice
 344	common	move_pages		sys_move_pages
 345	common	getcpu			sys_getcpu
-346	common	epoll_pwait		sys_epoll_pwait
+346	common	epoll_pwait		sys_epoll_pwait		sys_oabi_epoll_pwait
 347	common	kexec_load		sys_kexec_load
 348	common	utimensat		sys_utimensat_time32
 349	common	signalfd		sys_signalfd
#1 lore raw
Quoted 6 lines · On Wed, Sep 15, 2021 at 3:06 PM <[email protected]> wrote:

The patch below does not apply to the 4.4-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

I think we're good without the backport. While this fixes a real bug, the only reason to actually need OABI support is to run old binaries, and those predate this syscall.

Arnd