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signal: simplify set_user_sigmask/restore_user_sigmask 

task->saved_sigmask and ->restore_sigmask are only used in the ret-from-
syscall paths.  This means that set_user_sigmask() can save ->blocked in
->saved_sigmask and do set_restore_sigmask() to indicate that ->blocked
was modified.

This way the callers do not need 2 sigset_t's passed to set/restore and
restore_user_sigmask() renamed to restore_saved_sigmask_unless() turns
into the trivial helper which just calls restore_saved_sigmask().

Link: http://lkml.kernel.org/r/20190606113206.GA9464@redhat.com
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: Deepa Dinamani <deepa.kernel@gmail.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Eric Wong <e@80x24.org>
Cc: Jason Baron <jbaron@akamai.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: David Laight <David.Laight@aculab.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Oleg Nesterov 2019-07-16 16:29:53 -07:00 committed by Linus Torvalds
parent e2d9018e81
commit b772434be0
8 changed files with 57 additions and 108 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

20
fs/aio.c
View File

@ -2094,7 +2094,6 @@ SYSCALL_DEFINE6(io_pgetevents,
const struct __aio_sigset __user *, usig)
{
struct __aio_sigset ksig = { NULL, };
sigset_t ksigmask, sigsaved;
struct timespec64 ts;
bool interrupted;
int ret;
@ -2105,14 +2104,14 @@ SYSCALL_DEFINE6(io_pgetevents,
if (usig && copy_from_user(&ksig, usig, sizeof(ksig)))
return -EFAULT;
ret = set_user_sigmask(ksig.sigmask, &ksigmask, &sigsaved, ksig.sigsetsize);
ret = set_user_sigmask(ksig.sigmask, ksig.sigsetsize);
if (ret)
return ret;
ret = do_io_getevents(ctx_id, min_nr, nr, events, timeout ? &ts : NULL);
interrupted = signal_pending(current);
restore_user_sigmask(ksig.sigmask, &sigsaved, interrupted);
restore_saved_sigmask_unless(interrupted);
if (interrupted && !ret)
ret = -ERESTARTNOHAND;
@ -2130,7 +2129,6 @@ SYSCALL_DEFINE6(io_pgetevents_time32,
const struct __aio_sigset __user *, usig)
{
struct __aio_sigset ksig = { NULL, };
sigset_t ksigmask, sigsaved;
struct timespec64 ts;
bool interrupted;
int ret;
@ -2142,14 +2140,14 @@ SYSCALL_DEFINE6(io_pgetevents_time32,
return -EFAULT;
ret = set_user_sigmask(ksig.sigmask, &ksigmask, &sigsaved, ksig.sigsetsize);
ret = set_user_sigmask(ksig.sigmask, ksig.sigsetsize);
if (ret)
return ret;
ret = do_io_getevents(ctx_id, min_nr, nr, events, timeout ? &ts : NULL);
interrupted = signal_pending(current);
restore_user_sigmask(ksig.sigmask, &sigsaved, interrupted);
restore_saved_sigmask_unless(interrupted);
if (interrupted && !ret)
ret = -ERESTARTNOHAND;
@ -2198,7 +2196,6 @@ COMPAT_SYSCALL_DEFINE6(io_pgetevents,
const struct __compat_aio_sigset __user *, usig)
{
struct __compat_aio_sigset ksig = { NULL, };
sigset_t ksigmask, sigsaved;
struct timespec64 t;
bool interrupted;
int ret;
@ -2209,14 +2206,14 @@ COMPAT_SYSCALL_DEFINE6(io_pgetevents,
if (usig && copy_from_user(&ksig, usig, sizeof(ksig)))
return -EFAULT;
ret = set_compat_user_sigmask(ksig.sigmask, &ksigmask, &sigsaved, ksig.sigsetsize);
ret = set_compat_user_sigmask(ksig.sigmask, ksig.sigsetsize);
if (ret)
return ret;
ret = do_io_getevents(ctx_id, min_nr, nr, events, timeout ? &t : NULL);
interrupted = signal_pending(current);
restore_user_sigmask(ksig.sigmask, &sigsaved, interrupted);
restore_saved_sigmask_unless(interrupted);
if (interrupted && !ret)
ret = -ERESTARTNOHAND;
@ -2234,7 +2231,6 @@ COMPAT_SYSCALL_DEFINE6(io_pgetevents_time64,
const struct __compat_aio_sigset __user *, usig)
{
struct __compat_aio_sigset ksig = { NULL, };
sigset_t ksigmask, sigsaved;
struct timespec64 t;
bool interrupted;
int ret;
@ -2245,14 +2241,14 @@ COMPAT_SYSCALL_DEFINE6(io_pgetevents_time64,
if (usig && copy_from_user(&ksig, usig, sizeof(ksig)))
return -EFAULT;
ret = set_compat_user_sigmask(ksig.sigmask, &ksigmask, &sigsaved, ksig.sigsetsize);
ret = set_compat_user_sigmask(ksig.sigmask, ksig.sigsetsize);
if (ret)
return ret;
ret = do_io_getevents(ctx_id, min_nr, nr, events, timeout ? &t : NULL);
interrupted = signal_pending(current);
restore_user_sigmask(ksig.sigmask, &sigsaved, interrupted);
restore_saved_sigmask_unless(interrupted);
if (interrupted && !ret)
ret = -ERESTARTNOHAND;

12
fs/eventpoll.c
View File

@ -2313,19 +2313,17 @@ SYSCALL_DEFINE6(epoll_pwait, int, epfd, struct epoll_event __user *, events,
size_t, sigsetsize)
{
int error;
sigset_t ksigmask, sigsaved;
/*
* If the caller wants a certain signal mask to be set during the wait,
* we apply it here.
*/
error = set_user_sigmask(sigmask, &ksigmask, &sigsaved, sigsetsize);
error = set_user_sigmask(sigmask, sigsetsize);
if (error)
return error;
error = do_epoll_wait(epfd, events, maxevents, timeout);
restore_user_sigmask(sigmask, &sigsaved, error == -EINTR);
restore_saved_sigmask_unless(error == -EINTR);
return error;
}
@ -2338,19 +2336,17 @@ COMPAT_SYSCALL_DEFINE6(epoll_pwait, int, epfd,
compat_size_t, sigsetsize)
{
long err;
sigset_t ksigmask, sigsaved;
/*
* If the caller wants a certain signal mask to be set during the wait,
* we apply it here.
*/
err = set_compat_user_sigmask(sigmask, &ksigmask, &sigsaved, sigsetsize);
err = set_compat_user_sigmask(sigmask, sigsetsize);
if (err)
return err;
err = do_epoll_wait(epfd, events, maxevents, timeout);
restore_user_sigmask(sigmask, &sigsaved, err == -EINTR);
restore_saved_sigmask_unless(err == -EINTR);
return err;
}

11
fs/io_uring.c
View File

@ -2400,7 +2400,6 @@ static int io_cqring_wait(struct io_ring_ctx *ctx, int min_events,
const sigset_t __user *sig, size_t sigsz)
{
struct io_cq_ring *ring = ctx->cq_ring;
sigset_t ksigmask, sigsaved;
int ret;
if (io_cqring_events(ring) >= min_events)
@ -2410,21 +2409,17 @@ static int io_cqring_wait(struct io_ring_ctx *ctx, int min_events,
#ifdef CONFIG_COMPAT
if (in_compat_syscall())
ret = set_compat_user_sigmask((const compat_sigset_t __user *)sig,
&ksigmask, &sigsaved, sigsz);
sigsz);
else
#endif
ret = set_user_sigmask(sig, &ksigmask,
&sigsaved, sigsz);
ret = set_user_sigmask(sig, sigsz);
if (ret)
return ret;
}
ret = wait_event_interruptible(ctx->wait, io_cqring_events(ring) >= min_events);
if (sig)
restore_user_sigmask(sig, &sigsaved, ret == -ERESTARTSYS);
restore_saved_sigmask_unless(ret == -ERESTARTSYS);
if (ret == -ERESTARTSYS)
ret = -EINTR;

34
fs/select.c
View File

@ -730,7 +730,6 @@ static long do_pselect(int n, fd_set __user *inp, fd_set __user *outp,
const sigset_t __user *sigmask, size_t sigsetsize,
enum poll_time_type type)
{
sigset_t ksigmask, sigsaved;
struct timespec64 ts, end_time, *to = NULL;
int ret;
@ -753,12 +752,12 @@ static long do_pselect(int n, fd_set __user *inp, fd_set __user *outp,
return -EINVAL;
}
ret = set_user_sigmask(sigmask, &ksigmask, &sigsaved, sigsetsize);
ret = set_user_sigmask(sigmask, sigsetsize);
if (ret)
return ret;
ret = core_sys_select(n, inp, outp, exp, to);
restore_user_sigmask(sigmask, &sigsaved, ret == -ERESTARTNOHAND);
restore_saved_sigmask_unless(ret == -ERESTARTNOHAND);
ret = poll_select_copy_remaining(&end_time, tsp, type, ret);
return ret;
@ -1086,7 +1085,6 @@ SYSCALL_DEFINE5(ppoll, struct pollfd __user *, ufds, unsigned int, nfds,
struct __kernel_timespec __user *, tsp, const sigset_t __user *, sigmask,
size_t, sigsetsize)
{
sigset_t ksigmask, sigsaved;
struct timespec64 ts, end_time, *to = NULL;
int ret;
@ -1099,17 +1097,16 @@ SYSCALL_DEFINE5(ppoll, struct pollfd __user *, ufds, unsigned int, nfds,
return -EINVAL;
}
ret = set_user_sigmask(sigmask, &ksigmask, &sigsaved, sigsetsize);
ret = set_user_sigmask(sigmask, sigsetsize);
if (ret)
return ret;
ret = do_sys_poll(ufds, nfds, to);
restore_user_sigmask(sigmask, &sigsaved, ret == -EINTR);
restore_saved_sigmask_unless(ret == -EINTR);
/* We can restart this syscall, usually */
if (ret == -EINTR)
ret = -ERESTARTNOHAND;
ret = poll_select_copy_remaining(&end_time, tsp, PT_TIMESPEC, ret);
return ret;
@ -1121,7 +1118,6 @@ SYSCALL_DEFINE5(ppoll_time32, struct pollfd __user *, ufds, unsigned int, nfds,
struct old_timespec32 __user *, tsp, const sigset_t __user *, sigmask,
size_t, sigsetsize)
{
sigset_t ksigmask, sigsaved;
struct timespec64 ts, end_time, *to = NULL;
int ret;
@ -1134,17 +1130,16 @@ SYSCALL_DEFINE5(ppoll_time32, struct pollfd __user *, ufds, unsigned int, nfds,
return -EINVAL;
}
ret = set_user_sigmask(sigmask, &ksigmask, &sigsaved, sigsetsize);
ret = set_user_sigmask(sigmask, sigsetsize);
if (ret)
return ret;
ret = do_sys_poll(ufds, nfds, to);
restore_user_sigmask(sigmask, &sigsaved, ret == -EINTR);
restore_saved_sigmask_unless(ret == -EINTR);
/* We can restart this syscall, usually */
if (ret == -EINTR)
ret = -ERESTARTNOHAND;
ret = poll_select_copy_remaining(&end_time, tsp, PT_OLD_TIMESPEC, ret);
return ret;
@ -1319,7 +1314,6 @@ static long do_compat_pselect(int n, compat_ulong_t __user *inp,
void __user *tsp, compat_sigset_t __user *sigmask,
compat_size_t sigsetsize, enum poll_time_type type)
{
sigset_t ksigmask, sigsaved;
struct timespec64 ts, end_time, *to = NULL;
int ret;
@ -1342,12 +1336,12 @@ static long do_compat_pselect(int n, compat_ulong_t __user *inp,
return -EINVAL;
}
ret = set_compat_user_sigmask(sigmask, &ksigmask, &sigsaved, sigsetsize);
ret = set_compat_user_sigmask(sigmask, sigsetsize);
if (ret)
return ret;
ret = compat_core_sys_select(n, inp, outp, exp, to);
restore_user_sigmask(sigmask, &sigsaved, ret == -ERESTARTNOHAND);
restore_saved_sigmask_unless(ret == -ERESTARTNOHAND);
ret = poll_select_copy_remaining(&end_time, tsp, type, ret);
return ret;
@ -1402,7 +1396,6 @@ COMPAT_SYSCALL_DEFINE5(ppoll_time32, struct pollfd __user *, ufds,
unsigned int, nfds, struct old_timespec32 __user *, tsp,
const compat_sigset_t __user *, sigmask, compat_size_t, sigsetsize)
{
sigset_t ksigmask, sigsaved;
struct timespec64 ts, end_time, *to = NULL;
int ret;
@ -1415,17 +1408,16 @@ COMPAT_SYSCALL_DEFINE5(ppoll_time32, struct pollfd __user *, ufds,
return -EINVAL;
}
ret = set_compat_user_sigmask(sigmask, &ksigmask, &sigsaved, sigsetsize);
ret = set_compat_user_sigmask(sigmask, sigsetsize);
if (ret)
return ret;
ret = do_sys_poll(ufds, nfds, to);
restore_user_sigmask(sigmask, &sigsaved, ret == -EINTR);
restore_saved_sigmask_unless(ret == -EINTR);
/* We can restart this syscall, usually */
if (ret == -EINTR)
ret = -ERESTARTNOHAND;
ret = poll_select_copy_remaining(&end_time, tsp, PT_OLD_TIMESPEC, ret);
return ret;
@ -1437,7 +1429,6 @@ COMPAT_SYSCALL_DEFINE5(ppoll_time64, struct pollfd __user *, ufds,
unsigned int, nfds, struct __kernel_timespec __user *, tsp,
const compat_sigset_t __user *, sigmask, compat_size_t, sigsetsize)
{
sigset_t ksigmask, sigsaved;
struct timespec64 ts, end_time, *to = NULL;
int ret;
@ -1450,17 +1441,16 @@ COMPAT_SYSCALL_DEFINE5(ppoll_time64, struct pollfd __user *, ufds,
return -EINVAL;
}
ret = set_compat_user_sigmask(sigmask, &ksigmask, &sigsaved, sigsetsize);
ret = set_compat_user_sigmask(sigmask, sigsetsize);
if (ret)
return ret;
ret = do_sys_poll(ufds, nfds, to);
restore_user_sigmask(sigmask, &sigsaved, ret == -EINTR);
restore_saved_sigmask_unless(ret == -EINTR);
/* We can restart this syscall, usually */
if (ret == -EINTR)
ret = -ERESTARTNOHAND;
ret = poll_select_copy_remaining(&end_time, tsp, PT_TIMESPEC, ret);
return ret;

3
include/linux/compat.h
View File

@ -138,8 +138,7 @@ typedef struct {
compat_sigset_word sig[_COMPAT_NSIG_WORDS];
} compat_sigset_t;
int set_compat_user_sigmask(const compat_sigset_t __user *usigmask,
sigset_t *set, sigset_t *oldset,
int set_compat_user_sigmask(const compat_sigset_t __user *umask,
size_t sigsetsize);
struct compat_sigaction {

12
include/linux/sched/signal.h
View File

@ -420,7 +420,6 @@ void task_join_group_stop(struct task_struct *task);
static inline void set_restore_sigmask(void)
{
set_thread_flag(TIF_RESTORE_SIGMASK);
WARN_ON(!test_thread_flag(TIF_SIGPENDING));
}
static inline void clear_tsk_restore_sigmask(struct task_struct *task)
@ -451,7 +450,6 @@ static inline bool test_and_clear_restore_sigmask(void)
static inline void set_restore_sigmask(void)
{
current->restore_sigmask = true;
WARN_ON(!test_thread_flag(TIF_SIGPENDING));
}
static inline void clear_tsk_restore_sigmask(struct task_struct *task)
{
@ -484,6 +482,16 @@ static inline void restore_saved_sigmask(void)
__set_current_blocked(&current->saved_sigmask);
}
extern int set_user_sigmask(const sigset_t __user *umask, size_t sigsetsize);
static inline void restore_saved_sigmask_unless(bool interrupted)
{
if (interrupted)
WARN_ON(!test_thread_flag(TIF_SIGPENDING));
else
restore_saved_sigmask();
}
static inline sigset_t *sigmask_to_save(void)
{
sigset_t *res = &current->blocked;

4
include/linux/signal.h
View File

@ -273,10 +273,6 @@ extern int group_send_sig_info(int sig, struct kernel_siginfo *info,
struct task_struct *p, enum pid_type type);
extern int __group_send_sig_info(int, struct kernel_siginfo *, struct task_struct *);
extern int sigprocmask(int, sigset_t *, sigset_t *);
extern int set_user_sigmask(const sigset_t __user *usigmask, sigset_t *set,
sigset_t *oldset, size_t sigsetsize);
extern void restore_user_sigmask(const void __user *usigmask,
sigset_t *sigsaved, bool interrupted);
extern void set_current_blocked(sigset_t *);
extern void __set_current_blocked(const sigset_t *);
extern int show_unhandled_signals;

69
kernel/signal.c
View File

@ -2951,80 +2951,49 @@ EXPORT_SYMBOL(sigprocmask);
*
* This is useful for syscalls such as ppoll, pselect, io_pgetevents and
* epoll_pwait where a new sigmask is passed from userland for the syscalls.
*
* Note that it does set_restore_sigmask() in advance, so it must be always
* paired with restore_saved_sigmask_unless() before return from syscall.
*/
int set_user_sigmask(const sigset_t __user *usigmask, sigset_t *set,
sigset_t *oldset, size_t sigsetsize)
int set_user_sigmask(const sigset_t __user *umask, size_t sigsetsize)
{
if (!usigmask)
return 0;
sigset_t kmask;
if (!umask)
return 0;
if (sigsetsize != sizeof(sigset_t))
return -EINVAL;
if (copy_from_user(set, usigmask, sizeof(sigset_t)))
if (copy_from_user(&kmask, umask, sizeof(sigset_t)))
return -EFAULT;
*oldset = current->blocked;
set_current_blocked(set);
set_restore_sigmask();
current->saved_sigmask = current->blocked;
set_current_blocked(&kmask);
return 0;
}
EXPORT_SYMBOL(set_user_sigmask);
#ifdef CONFIG_COMPAT
int set_compat_user_sigmask(const compat_sigset_t __user *usigmask,
sigset_t *set, sigset_t *oldset,
int set_compat_user_sigmask(const compat_sigset_t __user *umask,
size_t sigsetsize)
{
if (!usigmask)
return 0;
sigset_t kmask;
if (!umask)
return 0;
if (sigsetsize != sizeof(compat_sigset_t))
return -EINVAL;
if (get_compat_sigset(set, usigmask))
if (get_compat_sigset(&kmask, umask))
return -EFAULT;
*oldset = current->blocked;
set_current_blocked(set);
set_restore_sigmask();
current->saved_sigmask = current->blocked;
set_current_blocked(&kmask);
return 0;
}
EXPORT_SYMBOL(set_compat_user_sigmask);
#endif
/*
* restore_user_sigmask:
* usigmask: sigmask passed in from userland.
* sigsaved: saved sigmask when the syscall started and changed the sigmask to
* usigmask.
*
* This is useful for syscalls such as ppoll, pselect, io_pgetevents and
* epoll_pwait where a new sigmask is passed in from userland for the syscalls.
*/
void restore_user_sigmask(const void __user *usigmask, sigset_t *sigsaved,
bool interrupted)
{
if (!usigmask)
return;
/*
* When signals are pending, do not restore them here.
* Restoring sigmask here can lead to delivering signals that the above
* syscalls are intended to block because of the sigmask passed in.
*/
if (interrupted) {
current->saved_sigmask = *sigsaved;
set_restore_sigmask();
return;
}
/*
* This is needed because the fast syscall return path does not restore
* saved_sigmask when signals are not pending.
*/
set_current_blocked(sigsaved);
}
EXPORT_SYMBOL(restore_user_sigmask);
/**
* sys_rt_sigprocmask - change the list of currently blocked signals
* @how: whether to add, remove, or set signals