To complement sys_futex_waitv() add sys_futex_wake(). This syscall
implements what was previously known as FUTEX_WAKE_BITSET except it
uses 'unsigned long' for the bitmask and takes FUTEX2 flags.
The 'unsigned long' allows FUTEX2_SIZE_U64 on 64bit platforms.
Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Acked-by: Geert Uytterhoeven <[email protected]>
---
arch/alpha/kernel/syscalls/syscall.tbl | 1
arch/arm/tools/syscall.tbl | 1
arch/arm64/include/asm/unistd.h | 2 -
arch/arm64/include/asm/unistd32.h | 2 +
arch/ia64/kernel/syscalls/syscall.tbl | 1
arch/m68k/kernel/syscalls/syscall.tbl | 1
arch/microblaze/kernel/syscalls/syscall.tbl | 1
arch/mips/kernel/syscalls/syscall_n32.tbl | 1
arch/mips/kernel/syscalls/syscall_n64.tbl | 1
arch/mips/kernel/syscalls/syscall_o32.tbl | 1
arch/parisc/kernel/syscalls/syscall.tbl | 1
arch/powerpc/kernel/syscalls/syscall.tbl | 1
arch/s390/kernel/syscalls/syscall.tbl | 1
arch/sh/kernel/syscalls/syscall.tbl | 1
arch/sparc/kernel/syscalls/syscall.tbl | 1
arch/x86/entry/syscalls/syscall_32.tbl | 1
arch/x86/entry/syscalls/syscall_64.tbl | 1
arch/xtensa/kernel/syscalls/syscall.tbl | 1
include/linux/syscalls.h | 3 ++
include/uapi/asm-generic/unistd.h | 5 ++--
kernel/futex/syscalls.c | 30 ++++++++++++++++++++++++++++
kernel/sys_ni.c | 1
22 files changed, 56 insertions(+), 3 deletions(-)
--- a/arch/alpha/kernel/syscalls/syscall.tbl
+++ b/arch/alpha/kernel/syscalls/syscall.tbl
@@ -491,3 +491,4 @@
559 common futex_waitv sys_futex_waitv
560 common set_mempolicy_home_node sys_ni_syscall
561 common cachestat sys_cachestat
+562 common futex_wake sys_futex_wake
--- a/arch/arm/tools/syscall.tbl
+++ b/arch/arm/tools/syscall.tbl
@@ -465,3 +465,4 @@
449 common futex_waitv sys_futex_waitv
450 common set_mempolicy_home_node sys_set_mempolicy_home_node
451 common cachestat sys_cachestat
+452 common futex_wake sys_futex_wake
--- a/arch/arm64/include/asm/unistd.h
+++ b/arch/arm64/include/asm/unistd.h
@@ -39,7 +39,7 @@
#define __ARM_NR_compat_set_tls (__ARM_NR_COMPAT_BASE + 5)
#define __ARM_NR_COMPAT_END (__ARM_NR_COMPAT_BASE + 0x800)
-#define __NR_compat_syscalls 452
+#define __NR_compat_syscalls 453
#endif
#define __ARCH_WANT_SYS_CLONE
--- a/arch/arm64/include/asm/unistd32.h
+++ b/arch/arm64/include/asm/unistd32.h
@@ -909,6 +909,8 @@ __SYSCALL(__NR_futex_waitv, sys_futex_wa
__SYSCALL(__NR_set_mempolicy_home_node, sys_set_mempolicy_home_node)
#define __NR_cachestat 451
__SYSCALL(__NR_cachestat, sys_cachestat)
+#define __NR_futex_wake 452
+__SYSCALL(__NR_futex_wake, sys_futex_wake)
/*
* Please add new compat syscalls above this comment and update
--- a/arch/ia64/kernel/syscalls/syscall.tbl
+++ b/arch/ia64/kernel/syscalls/syscall.tbl
@@ -372,3 +372,4 @@
449 common futex_waitv sys_futex_waitv
450 common set_mempolicy_home_node sys_set_mempolicy_home_node
451 common cachestat sys_cachestat
+452 common futex_wake sys_futex_wake
--- a/arch/m68k/kernel/syscalls/syscall.tbl
+++ b/arch/m68k/kernel/syscalls/syscall.tbl
@@ -451,3 +451,4 @@
449 common futex_waitv sys_futex_waitv
450 common set_mempolicy_home_node sys_set_mempolicy_home_node
451 common cachestat sys_cachestat
+452 common futex_wake sys_futex_wake
--- a/arch/microblaze/kernel/syscalls/syscall.tbl
+++ b/arch/microblaze/kernel/syscalls/syscall.tbl
@@ -457,3 +457,4 @@
449 common futex_waitv sys_futex_waitv
450 common set_mempolicy_home_node sys_set_mempolicy_home_node
451 common cachestat sys_cachestat
+452 common futex_wake sys_futex_wake
--- a/arch/mips/kernel/syscalls/syscall_n32.tbl
+++ b/arch/mips/kernel/syscalls/syscall_n32.tbl
@@ -390,3 +390,4 @@
449 n32 futex_waitv sys_futex_waitv
450 n32 set_mempolicy_home_node sys_set_mempolicy_home_node
451 n32 cachestat sys_cachestat
+452 n32 futex_wake sys_futex_wake
--- a/arch/mips/kernel/syscalls/syscall_n64.tbl
+++ b/arch/mips/kernel/syscalls/syscall_n64.tbl
@@ -366,3 +366,4 @@
449 n64 futex_waitv sys_futex_waitv
450 common set_mempolicy_home_node sys_set_mempolicy_home_node
451 n64 cachestat sys_cachestat
+452 n64 futex_wake sys_futex_wake
--- a/arch/mips/kernel/syscalls/syscall_o32.tbl
+++ b/arch/mips/kernel/syscalls/syscall_o32.tbl
@@ -439,3 +439,4 @@
449 o32 futex_waitv sys_futex_waitv
450 o32 set_mempolicy_home_node sys_set_mempolicy_home_node
451 o32 cachestat sys_cachestat
+452 o32 futex_wake sys_futex_wake
--- a/arch/parisc/kernel/syscalls/syscall.tbl
+++ b/arch/parisc/kernel/syscalls/syscall.tbl
@@ -450,3 +450,4 @@
449 common futex_waitv sys_futex_waitv
450 common set_mempolicy_home_node sys_set_mempolicy_home_node
451 common cachestat sys_cachestat
+452 common futex_wake sys_futex_wake
--- a/arch/powerpc/kernel/syscalls/syscall.tbl
+++ b/arch/powerpc/kernel/syscalls/syscall.tbl
@@ -538,3 +538,4 @@
449 common futex_waitv sys_futex_waitv
450 nospu set_mempolicy_home_node sys_set_mempolicy_home_node
451 common cachestat sys_cachestat
+452 common futex_wake sys_futex_wake
--- a/arch/s390/kernel/syscalls/syscall.tbl
+++ b/arch/s390/kernel/syscalls/syscall.tbl
@@ -454,3 +454,4 @@
449 common futex_waitv sys_futex_waitv sys_futex_waitv
450 common set_mempolicy_home_node sys_set_mempolicy_home_node sys_set_mempolicy_home_node
451 common cachestat sys_cachestat sys_cachestat
+452 common futex_wake sys_futex_wake sys_futex_wake
--- a/arch/sh/kernel/syscalls/syscall.tbl
+++ b/arch/sh/kernel/syscalls/syscall.tbl
@@ -454,3 +454,4 @@
449 common futex_waitv sys_futex_waitv
450 common set_mempolicy_home_node sys_set_mempolicy_home_node
451 common cachestat sys_cachestat
+452 common futex_wake sys_futex_wake
--- a/arch/sparc/kernel/syscalls/syscall.tbl
+++ b/arch/sparc/kernel/syscalls/syscall.tbl
@@ -497,3 +497,4 @@
449 common futex_waitv sys_futex_waitv
450 common set_mempolicy_home_node sys_set_mempolicy_home_node
451 common cachestat sys_cachestat
+452 common futex_wake sys_futex_wake
--- a/arch/x86/entry/syscalls/syscall_32.tbl
+++ b/arch/x86/entry/syscalls/syscall_32.tbl
@@ -456,3 +456,4 @@
449 i386 futex_waitv sys_futex_waitv
450 i386 set_mempolicy_home_node sys_set_mempolicy_home_node
451 i386 cachestat sys_cachestat
+452 i386 futex_wake sys_futex_wake
--- a/arch/x86/entry/syscalls/syscall_64.tbl
+++ b/arch/x86/entry/syscalls/syscall_64.tbl
@@ -373,6 +373,7 @@
449 common futex_waitv sys_futex_waitv
450 common set_mempolicy_home_node sys_set_mempolicy_home_node
451 common cachestat sys_cachestat
+452 common futex_wake sys_futex_wake
#
# Due to a historical design error, certain syscalls are numbered differently
--- a/arch/xtensa/kernel/syscalls/syscall.tbl
+++ b/arch/xtensa/kernel/syscalls/syscall.tbl
@@ -422,3 +422,4 @@
449 common futex_waitv sys_futex_waitv
450 common set_mempolicy_home_node sys_set_mempolicy_home_node
451 common cachestat sys_cachestat
+452 common futex_wake sys_futex_wake
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -563,6 +563,9 @@ asmlinkage long sys_set_robust_list(stru
asmlinkage long sys_futex_waitv(struct futex_waitv *waiters,
unsigned int nr_futexes, unsigned int flags,
struct __kernel_timespec __user *timeout, clockid_t clockid);
+
+asmlinkage long sys_futex_wake(void __user *uaddr, unsigned long mask, int nr, unsigned int flags);
+
asmlinkage long sys_nanosleep(struct __kernel_timespec __user *rqtp,
struct __kernel_timespec __user *rmtp);
asmlinkage long sys_nanosleep_time32(struct old_timespec32 __user *rqtp,
--- a/include/uapi/asm-generic/unistd.h
+++ b/include/uapi/asm-generic/unistd.h
@@ -816,12 +816,13 @@ __SYSCALL(__NR_process_mrelease, sys_pro
__SYSCALL(__NR_futex_waitv, sys_futex_waitv)
#define __NR_set_mempolicy_home_node 450
__SYSCALL(__NR_set_mempolicy_home_node, sys_set_mempolicy_home_node)
-
#define __NR_cachestat 451
__SYSCALL(__NR_cachestat, sys_cachestat)
+#define __NR_futex_wake 452
+__SYSCALL(__NR_futex_wake, sys_futex_wake)
#undef __NR_syscalls
-#define __NR_syscalls 452
+#define __NR_syscalls 453
/*
* 32 bit systems traditionally used different
--- a/kernel/futex/syscalls.c
+++ b/kernel/futex/syscalls.c
@@ -306,6 +306,36 @@ SYSCALL_DEFINE5(futex_waitv, struct fute
return ret;
}
+/*
+ * sys_futex_wake - Wake a number of futexes
+ * @uaddr: Address of the futex(es) to wake
+ * @mask: bitmask
+ * @nr: Number of the futexes to wake
+ * @flags: FUTEX2 flags
+ *
+ * Identical to the traditional FUTEX_WAKE_BITSET op, except it is part of the
+ * futex2 family of calls.
+ */
+
+SYSCALL_DEFINE4(futex_wake,
+ void __user *, uaddr,
+ unsigned long, mask,
+ int, nr,
+ unsigned int, flags)
+{
+ if (flags & ~FUTEX2_VALID_MASK)
+ return -EINVAL;
+
+ flags = futex2_to_flags(flags);
+ if (!futex_flags_valid(flags))
+ return -EINVAL;
+
+ if (!futex_validate_input(flags, mask))
+ return -EINVAL;
+
+ return futex_wake(uaddr, flags, nr, mask);
+}
+
#ifdef CONFIG_COMPAT
COMPAT_SYSCALL_DEFINE2(set_robust_list,
struct compat_robust_list_head __user *, head,
--- a/kernel/sys_ni.c
+++ b/kernel/sys_ni.c
@@ -87,6 +87,7 @@ COND_SYSCALL_COMPAT(set_robust_list);
COND_SYSCALL(get_robust_list);
COND_SYSCALL_COMPAT(get_robust_list);
COND_SYSCALL(futex_waitv);
+COND_SYSCALL(futex_wake);
COND_SYSCALL(kexec_load);
COND_SYSCALL_COMPAT(kexec_load);
COND_SYSCALL(init_module);
On Mon, Aug 07 2023 at 14:18, Peter Zijlstra wrote:
> To complement sys_futex_waitv() add sys_futex_wake(). This syscall
> implements what was previously known as FUTEX_WAKE_BITSET except it
> uses 'unsigned long' for the bitmask and takes FUTEX2 flags.
>
> The 'unsigned long' allows FUTEX2_SIZE_U64 on 64bit platforms.
>
> Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
> Acked-by: Geert Uytterhoeven <[email protected]>
Reviewed-by: Thomas Gleixner <[email protected]>
Hi Peter,
Em 07/08/2023 09:18, Peter Zijlstra escreveu:
> To complement sys_futex_waitv() add sys_futex_wake(). This syscall
> implements what was previously known as FUTEX_WAKE_BITSET except it
> uses 'unsigned long' for the bitmask and takes FUTEX2 flags.
>
> The 'unsigned long' allows FUTEX2_SIZE_U64 on 64bit platforms.
>
> Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
> Acked-by: Geert Uytterhoeven <[email protected]>
> ---
[...]
> +/*
> + * sys_futex_wake - Wake a number of futexes
> + * @uaddr: Address of the futex(es) to wake
> + * @mask: bitmask
> + * @nr: Number of the futexes to wake
> + * @flags: FUTEX2 flags
> + *
> + * Identical to the traditional FUTEX_WAKE_BITSET op, except it is part of the
> + * futex2 family of calls.
> + */
> +
> +SYSCALL_DEFINE4(futex_wake,
> + void __user *, uaddr,
> + unsigned long, mask,
> + int, nr,
> + unsigned int, flags)
> +{
Do you think we could have a
if (!nr)
return 0;
here? Otherwise, calling futex_wake(&f, 0, flags) will wake 1 futex (if
available), which is a strange undocumented behavior in my opinion.
> + if (flags & ~FUTEX2_VALID_MASK)
> + return -EINVAL;
> +
> + flags = futex2_to_flags(flags);
> + if (!futex_flags_valid(flags))
> + return -EINVAL;
> +
> + if (!futex_validate_input(flags, mask))
> + return -EINVAL;
> +
> + return futex_wake(uaddr, flags, nr, mask);
> +}
> +
> #ifdef CONFIG_COMPAT
> COMPAT_SYSCALL_DEFINE2(set_robust_list,
> struct compat_robust_list_head __user *, head,
> --- a/kernel/sys_ni.c
> +++ b/kernel/sys_ni.c
> @@ -87,6 +87,7 @@ COND_SYSCALL_COMPAT(set_robust_list);
> COND_SYSCALL(get_robust_list);
> COND_SYSCALL_COMPAT(get_robust_list);
> COND_SYSCALL(futex_waitv);
> +COND_SYSCALL(futex_wake);
> COND_SYSCALL(kexec_load);
> COND_SYSCALL_COMPAT(kexec_load);
> COND_SYSCALL(init_module);
>
>
On Wed, Aug 09, 2023 at 07:25:19PM -0300, Andr? Almeida wrote:
> Hi Peter,
>
> Em 07/08/2023 09:18, Peter Zijlstra escreveu:
> > To complement sys_futex_waitv() add sys_futex_wake(). This syscall
> > implements what was previously known as FUTEX_WAKE_BITSET except it
> > uses 'unsigned long' for the bitmask and takes FUTEX2 flags.
> >
> > The 'unsigned long' allows FUTEX2_SIZE_U64 on 64bit platforms.
> >
> > Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
> > Acked-by: Geert Uytterhoeven <[email protected]>
> > ---
>
> [...]
>
> > +/*
> > + * sys_futex_wake - Wake a number of futexes
> > + * @uaddr: Address of the futex(es) to wake
> > + * @mask: bitmask
> > + * @nr: Number of the futexes to wake
> > + * @flags: FUTEX2 flags
> > + *
> > + * Identical to the traditional FUTEX_WAKE_BITSET op, except it is part of the
> > + * futex2 family of calls.
> > + */
> > +
> > +SYSCALL_DEFINE4(futex_wake,
> > + void __user *, uaddr,
> > + unsigned long, mask,
> > + int, nr,
> > + unsigned int, flags)
> > +{
>
> Do you think we could have a
>
> if (!nr)
> return 0;
>
> here? Otherwise, calling futex_wake(&f, 0, flags) will wake 1 futex (if
> available), which is a strange undocumented behavior in my opinion.
Oh 'cute' that.. yeah, but how about I put it ...
> > + if (flags & ~FUTEX2_VALID_MASK)
> > + return -EINVAL;
> > +
> > + flags = futex2_to_flags(flags);
> > + if (!futex_flags_valid(flags))
> > + return -EINVAL;
> > +
> > + if (!futex_validate_input(flags, mask))
> > + return -EINVAL;
here, because otherwise we get:
sys_futex_wake(&f, 0xFFFF, 0, FUTEX2_SIZE_U8)
to return 0, even though that is 'obviously' nonsensical and should
return -EINVAL. Or even garbage flags would be 'accepted'.
(because 0xFFFF is larger than U8 can accomodate)
> > +
> > + return futex_wake(uaddr, flags, nr, mask);
> > +}
Em 10/08/2023 09:13, Peter Zijlstra escreveu:
> On Wed, Aug 09, 2023 at 07:25:19PM -0300, André Almeida wrote:
>> Hi Peter,
>>
>> Em 07/08/2023 09:18, Peter Zijlstra escreveu:
>>> To complement sys_futex_waitv() add sys_futex_wake(). This syscall
>>> implements what was previously known as FUTEX_WAKE_BITSET except it
>>> uses 'unsigned long' for the bitmask and takes FUTEX2 flags.
>>>
>>> The 'unsigned long' allows FUTEX2_SIZE_U64 on 64bit platforms.
>>>
>>> Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
>>> Acked-by: Geert Uytterhoeven <[email protected]>
>>> ---
>>
>> [...]
>>
>>> +/*
>>> + * sys_futex_wake - Wake a number of futexes
>>> + * @uaddr: Address of the futex(es) to wake
>>> + * @mask: bitmask
>>> + * @nr: Number of the futexes to wake
>>> + * @flags: FUTEX2 flags
>>> + *
>>> + * Identical to the traditional FUTEX_WAKE_BITSET op, except it is part of the
>>> + * futex2 family of calls.
>>> + */
>>> +
>>> +SYSCALL_DEFINE4(futex_wake,
>>> + void __user *, uaddr,
>>> + unsigned long, mask,
>>> + int, nr,
>>> + unsigned int, flags)
>>> +{
>>
>> Do you think we could have a
>>
>> if (!nr)
>> return 0;
>>
>> here? Otherwise, calling futex_wake(&f, 0, flags) will wake 1 futex (if
>> available), which is a strange undocumented behavior in my opinion.
>
> Oh 'cute' that.. yeah, but how about I put it ...
>
>>> + if (flags & ~FUTEX2_VALID_MASK)
>>> + return -EINVAL;
>>> +
>>> + flags = futex2_to_flags(flags);
>>> + if (!futex_flags_valid(flags))
>>> + return -EINVAL;
>>> +
>>> + if (!futex_validate_input(flags, mask))
>>> + return -EINVAL;
>
> here, because otherwise we get:
>
> sys_futex_wake(&f, 0xFFFF, 0, FUTEX2_SIZE_U8)
>
> to return 0, even though that is 'obviously' nonsensical and should
> return -EINVAL. Or even garbage flags would be 'accepted'.
>
> (because 0xFFFF is larger than U8 can accomodate)
>
That make sense to me, but we would also want to validate the value of
f, if it's NULL or something strange to return -EINVAL... but this
happens only inside get_futex_key()...
To make this right, I think we would need to move this verification to
the syscall validation part:
if (unlikely((address % sizeof(u32)) != 0))
return -EINVAL;
if (unlikely(!access_ok(uaddr, sizeof(u32))))
return -EFAULT;
And have u32 replaced with the proper size being used.
>>> +
>>> + return futex_wake(uaddr, flags, nr, mask);
>>> +}