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 stable@vger.kernel.org.

thanks,

greg k-h

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

From b6e47f3c11c17965acb2a12001af3b1cd5658f37 Mon Sep 17 00:00:00 2001

From: Arnd Bergmann arnd@arndb.de 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: stable@vger.kernel.org Reviewed-by: Christoph Hellwig hch@lst.de Signed-off-by: Arnd Bergmann arnd@arndb.de Signed-off-by: Russell King (Oracle) rmk+kernel@armlinux.org.uk

diff --git a/arch/arm/kernel/sys_oabi-compat.c b/arch/arm/kernel/sys_oabi-compat.c index 075a2e0ed2c1..443203fafb6b 100644 --- a/arch/arm/kernel/sys_oabi-compat.c +++ b/arch/arm/kernel/sys_oabi-compat.c @@ -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; diff --git a/arch/arm/tools/syscall.tbl b/arch/arm/tools/syscall.tbl index c5df1179fc5d..11d0b960b2c2 100644 --- a/arch/arm/tools/syscall.tbl +++ b/arch/arm/tools/syscall.tbl @@ -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