This is a note to let you know that I've just added the patch titled kernel, fs: Introduce and use set_restart_fn() and arch_set_restart_data() to the 4.19-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: kernel-fs-introduce-and-use-set_restart_fn-and-arch_set_restart_data.patch and it can be found in the queue-4.19 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From 5abbe51a526253b9f003e9a0a195638dc882d660 Mon Sep 17 00:00:00 2001 From: Oleg Nesterov <oleg@xxxxxxxxxx> Date: Mon, 1 Feb 2021 18:46:41 +0100 Subject: kernel, fs: Introduce and use set_restart_fn() and arch_set_restart_data() From: Oleg Nesterov <oleg@xxxxxxxxxx> commit 5abbe51a526253b9f003e9a0a195638dc882d660 upstream. Preparation for fixing get_nr_restart_syscall() on X86 for COMPAT. Add a new helper which sets restart_block->fn and calls a dummy arch_set_restart_data() helper. Fixes: 609c19a385c8 ("x86/ptrace: Stop setting TS_COMPAT in ptrace code") Signed-off-by: Oleg Nesterov <oleg@xxxxxxxxxx> Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Cc: stable@xxxxxxxxxxxxxxx Link: https://lore.kernel.org/r/20210201174641.GA17871@xxxxxxxxxx Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- fs/select.c | 10 ++++------ include/linux/thread_info.h | 13 +++++++++++++ kernel/futex.c | 3 +-- kernel/time/alarmtimer.c | 2 +- kernel/time/hrtimer.c | 2 +- kernel/time/posix-cpu-timers.c | 2 +- 6 files changed, 21 insertions(+), 11 deletions(-) --- a/fs/select.c +++ b/fs/select.c @@ -1003,10 +1003,9 @@ static long do_restart_poll(struct resta ret = do_sys_poll(ufds, nfds, to); - if (ret == -EINTR) { - restart_block->fn = do_restart_poll; - ret = -ERESTART_RESTARTBLOCK; - } + if (ret == -EINTR) + ret = set_restart_fn(restart_block, do_restart_poll); + return ret; } @@ -1028,7 +1027,6 @@ SYSCALL_DEFINE3(poll, struct pollfd __us struct restart_block *restart_block; restart_block = ¤t->restart_block; - restart_block->fn = do_restart_poll; restart_block->poll.ufds = ufds; restart_block->poll.nfds = nfds; @@ -1039,7 +1037,7 @@ SYSCALL_DEFINE3(poll, struct pollfd __us } else restart_block->poll.has_timeout = 0; - ret = -ERESTART_RESTARTBLOCK; + ret = set_restart_fn(restart_block, do_restart_poll); } return ret; } --- a/include/linux/thread_info.h +++ b/include/linux/thread_info.h @@ -11,6 +11,7 @@ #include <linux/types.h> #include <linux/bug.h> #include <linux/restart_block.h> +#include <linux/errno.h> #ifdef CONFIG_THREAD_INFO_IN_TASK /* @@ -39,6 +40,18 @@ enum { #ifdef __KERNEL__ +#ifndef arch_set_restart_data +#define arch_set_restart_data(restart) do { } while (0) +#endif + +static inline long set_restart_fn(struct restart_block *restart, + long (*fn)(struct restart_block *)) +{ + restart->fn = fn; + arch_set_restart_data(restart); + return -ERESTART_RESTARTBLOCK; +} + #ifndef THREAD_ALIGN #define THREAD_ALIGN THREAD_SIZE #endif --- a/kernel/futex.c +++ b/kernel/futex.c @@ -2857,14 +2857,13 @@ retry: goto out; restart = ¤t->restart_block; - restart->fn = futex_wait_restart; restart->futex.uaddr = uaddr; restart->futex.val = val; restart->futex.time = *abs_time; restart->futex.bitset = bitset; restart->futex.flags = flags | FLAGS_HAS_TIMEOUT; - ret = -ERESTART_RESTARTBLOCK; + ret = set_restart_fn(restart, futex_wait_restart); out: if (to) { --- a/kernel/time/alarmtimer.c +++ b/kernel/time/alarmtimer.c @@ -822,9 +822,9 @@ static int alarm_timer_nsleep(const cloc if (flags == TIMER_ABSTIME) return -ERESTARTNOHAND; - restart->fn = alarm_timer_nsleep_restart; restart->nanosleep.clockid = type; restart->nanosleep.expires = exp; + set_restart_fn(restart, alarm_timer_nsleep_restart); return ret; } --- a/kernel/time/hrtimer.c +++ b/kernel/time/hrtimer.c @@ -1771,9 +1771,9 @@ long hrtimer_nanosleep(const struct time } restart = ¤t->restart_block; - restart->fn = hrtimer_nanosleep_restart; restart->nanosleep.clockid = t.timer.base->clockid; restart->nanosleep.expires = hrtimer_get_expires_tv64(&t.timer); + set_restart_fn(restart, hrtimer_nanosleep_restart); out: destroy_hrtimer_on_stack(&t.timer); return ret; --- a/kernel/time/posix-cpu-timers.c +++ b/kernel/time/posix-cpu-timers.c @@ -1371,8 +1371,8 @@ static int posix_cpu_nsleep(const clocki if (flags & TIMER_ABSTIME) return -ERESTARTNOHAND; - restart_block->fn = posix_cpu_nsleep_restart; restart_block->nanosleep.clockid = which_clock; + set_restart_fn(restart_block, posix_cpu_nsleep_restart); } return error; } Patches currently in stable-queue which might be from oleg@xxxxxxxxxx are queue-4.19/kernel-fs-introduce-and-use-set_restart_fn-and-arch_set_restart_data.patch queue-4.19/x86-introduce-ts_compat_restart-to-fix-get_nr_restart_syscall.patch queue-4.19/x86-move-ts_compat-back-to-asm-thread_info.h.patch