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sysctl(2): unlock KERN_SPLASSERT
> Date: Sun, 29 Dec 2024 20:43:40 +0300
> From: Vitaliy Makkoveev <mvs@openbsd.org>
>
> `splassert_ctl' is atomically accessed integer which accessed lockless
> for a long time.
Sorry, but no, I don't think this is ok. This solves nothing, but it
does add an extra include to <machine/intr.h> that increases the risk
that folks start failing to explicitly include <sys/atomic.h> in
places where it is needed.
> Index: sys/arch/alpha/include/intr.h
> ===================================================================
> RCS file: /cvs/src/sys/arch/alpha/include/intr.h,v
> diff -u -p -r1.50 intr.h
> --- sys/arch/alpha/include/intr.h 17 May 2024 20:07:33 -0000 1.50
> +++ sys/arch/alpha/include/intr.h 29 Dec 2024 17:16:16 -0000
> @@ -147,6 +147,9 @@ void intr_barrier(void *);
>
> /* SPL asserts */
> #ifdef DIAGNOSTIC
> +
> +#include <sys/atomic.h>
> +
> /*
> * Although this function is implemented in MI code, it must be in this MD
> * header because we don't want this header to include MI includes.
> @@ -156,7 +159,7 @@ extern int splassert_ctl;
> void splassert_check(int, const char *);
> #define splassert(__wantipl) \
> do { \
> - if (splassert_ctl > 0) { \
> + if (atomic_load_int(&splassert_ctl) > 0) { \
> splassert_check(__wantipl, __func__); \
> } \
> } while (0)
> Index: sys/arch/amd64/include/intr.h
> ===================================================================
> RCS file: /cvs/src/sys/arch/amd64/include/intr.h,v
> diff -u -p -r1.34 intr.h
> --- sys/arch/amd64/include/intr.h 26 May 2024 13:37:31 -0000 1.34
> +++ sys/arch/amd64/include/intr.h 29 Dec 2024 17:16:16 -0000
> @@ -152,6 +152,9 @@ void softintr(int);
>
> /* SPL asserts */
> #ifdef DIAGNOSTIC
> +
> +#include <sys/atomic.h>
> +
> /*
> * Although this function is implemented in MI code, it must be in this MD
> * header because we don't want this header to include MI includes.
> @@ -160,7 +163,7 @@ void splassert_fail(int, int, const char
> extern int splassert_ctl;
> void splassert_check(int, const char *);
> #define splassert(__wantipl) do { \
> - if (splassert_ctl > 0) { \
> + if (atomic_load_int(&splassert_ctl) > 0) { \
> splassert_check(__wantipl, __func__); \
> } \
> } while (0)
> Index: sys/arch/arm64/include/intr.h
> ===================================================================
> RCS file: /cvs/src/sys/arch/arm64/include/intr.h,v
> diff -u -p -r1.23 intr.h
> --- sys/arch/arm64/include/intr.h 14 Oct 2024 10:08:13 -0000 1.23
> +++ sys/arch/arm64/include/intr.h 29 Dec 2024 17:16:16 -0000
> @@ -199,6 +199,9 @@ extern void (*intr_send_ipi_func)(struct
> #define ARM_IPI_HALT 2
>
> #ifdef DIAGNOSTIC
> +
> +#include <sys/atomic.h>
> +
> /*
> * Although this function is implemented in MI code, it must be in this MD
> * header because we don't want this header to include MI includes.
> @@ -207,7 +210,7 @@ void splassert_fail(int, int, const char
> extern int splassert_ctl;
> void arm_splassert_check(int, const char *);
> #define splassert(__wantipl) do { \
> - if (splassert_ctl > 0) { \
> + if (atomic_load_int(&splassert_ctl) > 0) { \
> arm_splassert_check(__wantipl, __func__); \
> } \
> } while (0)
> Index: sys/arch/armv7/include/intr.h
> ===================================================================
> RCS file: /cvs/src/sys/arch/armv7/include/intr.h,v
> diff -u -p -r1.15 intr.h
> --- sys/arch/armv7/include/intr.h 14 Oct 2024 10:08:13 -0000 1.15
> +++ sys/arch/armv7/include/intr.h 29 Dec 2024 17:16:16 -0000
> @@ -202,6 +202,9 @@ extern void (*intr_send_ipi_func)(struct
> #define ARM_IPI_DDB 1
>
> #ifdef DIAGNOSTIC
> +
> +#include <sys/atomic.h>
> +
> /*
> * Although this function is implemented in MI code, it must be in this MD
> * header because we don't want this header to include MI includes.
> @@ -210,8 +213,8 @@ void splassert_fail(int, int, const char
> extern int splassert_ctl;
> void arm_splassert_check(int, const char *);
> #define splassert(__wantipl) do { \
> - if (splassert_ctl > 0) { \
> - arm_splassert_check(__wantipl, __func__); \
> + if (atomic_load_int(&splassert_ctl) > 0) { \
> + arm_splassert_check(__wantipl, __func__); \
> } \
> } while (0)
> #define splsoftassert(wantipl) splassert(wantipl)
> Index: sys/arch/hppa/include/intr.h
> ===================================================================
> RCS file: /cvs/src/sys/arch/hppa/include/intr.h,v
> diff -u -p -r1.44 intr.h
> --- sys/arch/hppa/include/intr.h 13 Jan 2018 15:18:11 -0000 1.44
> +++ sys/arch/hppa/include/intr.h 29 Dec 2024 17:16:16 -0000
> @@ -71,11 +71,14 @@
> extern volatile u_long imask[NIPL];
>
> #ifdef DIAGNOSTIC
> +
> +#include <sys/atomic.h>
> +
> void splassert_fail(int, int, const char *);
> extern int splassert_ctl;
> void splassert_check(int, const char *);
> #define splassert(__wantipl) do { \
> - if (splassert_ctl > 0) { \
> + if (atomic_load_int(&splassert_ctl) > 0) { \
> splassert_check(__wantipl, __func__); \
> } \
> } while (0)
> Index: sys/arch/i386/include/intr.h
> ===================================================================
> RCS file: /cvs/src/sys/arch/i386/include/intr.h,v
> diff -u -p -r1.50 intr.h
> --- sys/arch/i386/include/intr.h 26 May 2024 13:37:32 -0000 1.50
> +++ sys/arch/i386/include/intr.h 29 Dec 2024 17:16:16 -0000
> @@ -64,6 +64,9 @@ extern void softintr(int);
>
> /* SPL asserts */
> #ifdef DIAGNOSTIC
> +
> +#include <sys/atomic.h>
> +
> /*
> * Although this function is implemented in MI code, it must be in this MD
> * header because we don't want this header to include MI includes.
> @@ -72,7 +75,7 @@ void splassert_fail(int, int, const char
> extern int splassert_ctl;
> void splassert_check(int, const char *);
> #define splassert(__wantipl) do { \
> - if (splassert_ctl > 0) { \
> + if (atomic_load_int(&splassert_ctl) > 0) { \
> splassert_check(__wantipl, __func__); \
> } \
> } while (0)
> Index: sys/arch/landisk/include/intr.h
> ===================================================================
> RCS file: /cvs/src/sys/arch/landisk/include/intr.h,v
> diff -u -p -r1.14 intr.h
> --- sys/arch/landisk/include/intr.h 20 Aug 2018 15:02:07 -0000 1.14
> +++ sys/arch/landisk/include/intr.h 29 Dec 2024 17:16:16 -0000
> @@ -66,6 +66,9 @@
> #define splx(x) _cpu_intr_resume(x)
>
> #ifdef DIAGNOSTIC
> +
> +#include <sys/atomic.h>
> +
> /*
> * Although this function is implemented in MI code, it must be in this MD
> * header because we don't want this header to include MI includes.
> @@ -75,7 +78,7 @@ extern int splassert_ctl;
> void splassert_check(int, const char *);
> #define splassert(__wantipl) \
> do { \
> - if (splassert_ctl > 0) { \
> + if (atomic_load_int(&splassert_ctl) > 0) { \
> splassert_check(__wantipl, __func__); \
> } \
> } while (0)
> Index: sys/arch/loongson/include/intr.h
> ===================================================================
> RCS file: /cvs/src/sys/arch/loongson/include/intr.h,v
> diff -u -p -r1.18 intr.h
> --- sys/arch/loongson/include/intr.h 5 Sep 2019 05:31:38 -0000 1.18
> +++ sys/arch/loongson/include/intr.h 29 Dec 2024 17:16:16 -0000
> @@ -129,6 +129,9 @@ void softintr_schedule(void *);
> void splinit(void);
>
> #ifdef DIAGNOSTIC
> +
> +#include <sys/atomic.h>
> +
> /*
> * Although this function is implemented in MI code, it must be in this MD
> * header because we don't want this header to include MI includes.
> @@ -137,7 +140,7 @@ void splassert_fail(int, int, const char
> extern int splassert_ctl;
> void splassert_check(int, const char *);
> #define splassert(__wantipl) do { \
> - if (splassert_ctl > 0) { \
> + if (atomic_load_int(&splassert_ctl) > 0) { \
> splassert_check(__wantipl, __func__); \
> } \
> } while (0)
> Index: sys/arch/m88k/include/intr.h
> ===================================================================
> RCS file: /cvs/src/sys/arch/m88k/include/intr.h,v
> diff -u -p -r1.14 intr.h
> --- sys/arch/m88k/include/intr.h 20 Aug 2018 15:02:07 -0000 1.14
> +++ sys/arch/m88k/include/intr.h 29 Dec 2024 17:16:16 -0000
> @@ -72,6 +72,9 @@ int spl0(void);
>
> /* SPL asserts */
> #ifdef DIAGNOSTIC
> +
> +#include <sys/atomic.h>
> +
> /*
> * Although this function is implemented in MI code, it must be in this MD
> * header because we don't want this header to include MI includes.
> @@ -80,7 +83,7 @@ void splassert_fail(int, int, const char
> extern int splassert_ctl;
> void splassert_check(int, const char *);
> #define splassert(__wantipl) do { \
> - if (splassert_ctl > 0) { \
> + if (atomic_load_int(&splassert_ctl) > 0) { \
> splassert_check(__wantipl, __func__); \
> } \
> } while (0)
> Index: sys/arch/octeon/include/intr.h
> ===================================================================
> RCS file: /cvs/src/sys/arch/octeon/include/intr.h,v
> diff -u -p -r1.22 intr.h
> --- sys/arch/octeon/include/intr.h 5 Sep 2019 05:31:38 -0000 1.22
> +++ sys/arch/octeon/include/intr.h 29 Dec 2024 17:16:16 -0000
> @@ -128,6 +128,9 @@ void softintr_schedule(void *);
> void splinit(void);
>
> #ifdef DIAGNOSTIC
> +
> +#include <sys/atomic.h>
> +
> /*
> * Although this function is implemented in MI code, it must be in this MD
> * header because we don't want this header to include MI includes.
> @@ -136,7 +139,7 @@ void splassert_fail(int, int, const char
> extern int splassert_ctl;
> void splassert_check(int, const char *);
> #define splassert(__wantipl) do { \
> - if (splassert_ctl > 0) { \
> + if (atomic_load_int(&splassert_ctl) > 0) { \
> splassert_check(__wantipl, __func__); \
> } \
> } while (0)
> Index: sys/arch/powerpc/include/intr.h
> ===================================================================
> RCS file: /cvs/src/sys/arch/powerpc/include/intr.h,v
> diff -u -p -r1.56 intr.h
> --- sys/arch/powerpc/include/intr.h 20 Aug 2018 15:02:07 -0000 1.56
> +++ sys/arch/powerpc/include/intr.h 29 Dec 2024 17:16:16 -0000
> @@ -90,6 +90,9 @@ void do_pending_int(void);
>
> /* SPL asserts */
> #ifdef DIAGNOSTIC
> +
> +#include <sys/atomic.h>
> +
> /*
> * Although this function is implemented in MI code, it must be in this MD
> * header because we don't want this header to include MI includes.
> @@ -98,7 +101,7 @@ void splassert_fail(int, int, const char
> extern int splassert_ctl;
> void splassert_check(int, const char *);
> #define splassert(__wantipl) do { \
> - if (splassert_ctl > 0) { \
> + if (atomic_load_int(&splassert_ctl) > 0) { \
> splassert_check(__wantipl, __func__); \
> } \
> } while (0)
> Index: sys/arch/powerpc64/include/intr.h
> ===================================================================
> RCS file: /cvs/src/sys/arch/powerpc64/include/intr.h,v
> diff -u -p -r1.14 intr.h
> --- sys/arch/powerpc64/include/intr.h 30 May 2021 15:06:53 -0000 1.14
> +++ sys/arch/powerpc64/include/intr.h 29 Dec 2024 17:16:16 -0000
> @@ -65,6 +65,9 @@ void splx(int);
> #define splhigh() splraise(IPL_HIGH)
>
> #ifdef DIAGNOSTIC
> +
> +#include <sys/atomic.h>
> +
> /*
> * Although this function is implemented in MI code, it must be in this MD
> * header because we don't want this header to include MI includes.
> @@ -73,7 +76,7 @@ void splassert_fail(int, int, const char
> extern int splassert_ctl;
> void splassert_check(int, const char *);
> #define splassert(__wantipl) do { \
> - if (splassert_ctl > 0) { \
> + if (atomic_load_int(&splassert_ctl) > 0) { \
> splassert_check(__wantipl, __func__); \
> } \
> } while (0)
> Index: sys/arch/riscv64/include/intr.h
> ===================================================================
> RCS file: /cvs/src/sys/arch/riscv64/include/intr.h,v
> diff -u -p -r1.8 intr.h
> --- sys/arch/riscv64/include/intr.h 16 Oct 2024 02:32:27 -0000 1.8
> +++ sys/arch/riscv64/include/intr.h 29 Dec 2024 17:16:16 -0000
> @@ -207,6 +207,9 @@ void riscv_intr_cpu_enable(void);
> void intr_send_ipi(struct cpu_info *, int);
>
> #ifdef DIAGNOSTIC
> +
> +#include <sys/atomic.h>
> +
> /*
> * Although this function is implemented in MI code, it must be in this MD
> * header because we don't want this header to include MI includes.
> @@ -215,7 +218,7 @@ void splassert_fail(int, int, const char
> extern int splassert_ctl;
> void riscv_splassert_check(int, const char *);
> #define splassert(__wantipl) do { \
> - if (splassert_ctl > 0) { \
> + if (atomic_load_int(&splassert_ctl) > 0) { \
> riscv_splassert_check(__wantipl, __func__); \
> } \
> } while (0)
> Index: sys/arch/sparc64/include/psl.h
> ===================================================================
> RCS file: /cvs/src/sys/arch/sparc64/include/psl.h,v
> diff -u -p -r1.37 psl.h
> --- sys/arch/sparc64/include/psl.h 6 Nov 2024 07:11:14 -0000 1.37
> +++ sys/arch/sparc64/include/psl.h 29 Dec 2024 17:16:16 -0000
> @@ -205,6 +205,9 @@
> #if defined(_KERNEL) && !defined(_LOCORE)
>
> #ifdef DIAGNOSTIC
> +
> +#include <sys/atomic.h>
> +
> /*
> * Although this function is implemented in MI code, it must be in this MD
> * header because we don't want this header to include MI includes.
> @@ -213,7 +216,7 @@ void splassert_fail(int, int, const char
> extern int splassert_ctl;
> void splassert_check(int, const char *);
> #define splassert(__wantipl) do { \
> - if (splassert_ctl > 0) { \
> + if (atomic_load_int(&splassert_ctl) > 0) { \
> splassert_check(__wantipl, __func__); \
> } \
> } while (0)
> Index: sys/dev/ic/iosf.c
> ===================================================================
> RCS file: /cvs/src/sys/dev/ic/iosf.c,v
> diff -u -p -r1.2 iosf.c
> --- sys/dev/ic/iosf.c 26 Jun 2024 01:40:49 -0000 1.2
> +++ sys/dev/ic/iosf.c 29 Dec 2024 17:16:16 -0000
> @@ -258,7 +258,7 @@ iosf_mbi_assert_punit_acquired(void)
> {
> int s;
>
> - if (splassert_ctl == 0)
> + if (atomic_load_int(&splassert_ctl) == 0)
> return;
>
> s = rw_status(&iosf_lock);
> Index: sys/kern/kern_sysctl.c
> ===================================================================
> RCS file: /cvs/src/sys/kern/kern_sysctl.c,v
> diff -u -p -r1.459 kern_sysctl.c
> --- sys/kern/kern_sysctl.c 28 Dec 2024 20:34:05 -0000 1.459
> +++ sys/kern/kern_sysctl.c 29 Dec 2024 17:16:17 -0000
> @@ -614,6 +614,7 @@ kern_sysctl(int *name, u_int namelen, vo
> case KERN_FSCALE:
> case KERN_CCPU:
> case KERN_NPROCS:
> + case KERN_SPLASSERT:
> case KERN_WXABORT:
> case KERN_NETLIVELOCKS:
> case KERN_GLOBAL_PTRACE:
> Index: sys/kern/subr_prf.c
> ===================================================================
> RCS file: /cvs/src/sys/kern/subr_prf.c,v
> diff -u -p -r1.106 subr_prf.c
> --- sys/kern/subr_prf.c 14 Aug 2022 01:58:28 -0000 1.106
> +++ sys/kern/subr_prf.c 29 Dec 2024 17:16:17 -0000
> @@ -89,6 +89,11 @@ struct mutex kprintf_mutex =
> MUTEX_INITIALIZER_FLAGS(IPL_HIGH, "kprintf", MTX_NOWITNESS);
>
> /*
> + * Locks used to protect data:
> + * a atomic
> + */
> +
> +/*
> * globals
> */
>
> @@ -119,9 +124,9 @@ int db_console = 0;
> * panic on spl assertion failure?
> */
> #ifdef SPLASSERT_WATCH
> -int splassert_ctl = 3;
> +int splassert_ctl = 3; /* [a] */
> #else
> -int splassert_ctl = 1;
> +int splassert_ctl = 1; /* [a] */
> #endif
>
> /*
> @@ -199,7 +204,7 @@ panic(const char *fmt, ...)
> bootopt |= RB_NOSYNC;
>
> /* do not trigger assertions, we know that we are inconsistent */
> - splassert_ctl = 0;
> + atomic_store_int(&splassert_ctl, 0);
>
> #ifdef BOOT_QUIET
> printf_flags |= TOCONS; /* make sure we see kernel printf output */
> @@ -243,7 +248,7 @@ splassert_fail(int wantipl, int haveipl,
> return;
>
> printf("splassert: %s: want %d have %d\n", func, wantipl, haveipl);
> - switch (splassert_ctl) {
> + switch (atomic_load_int(&splassert_ctl)) {
> case 1:
> break;
> case 2:
> Index: sys/kern/uipc_socket2.c
> ===================================================================
> RCS file: /cvs/src/sys/kern/uipc_socket2.c,v
> diff -u -p -r1.161 uipc_socket2.c
> --- sys/kern/uipc_socket2.c 26 Dec 2024 12:16:17 -0000 1.161
> +++ sys/kern/uipc_socket2.c 29 Dec 2024 17:16:17 -0000
> @@ -460,7 +460,7 @@ soassertlocked(struct socket *so)
> if (rw_status(&netlock) == RW_READ) {
> NET_ASSERT_LOCKED();
>
> - if (splassert_ctl > 0 &&
> + if (atomic_load_int(&splassert_ctl) > 0 &&
> rw_status(&so->so_lock) != RW_WRITE)
> splassert_fail(0, RW_WRITE, __func__);
> } else
> @@ -503,7 +503,8 @@ void
> sbmtxassertlocked(struct socket *so, struct sockbuf *sb)
> {
> if (sb->sb_flags & SB_MTXLOCK) {
> - if (splassert_ctl > 0 && mtx_owned(&sb->sb_mtx) == 0)
> + if (atomic_load_int(&splassert_ctl) > 0 &&
> + mtx_owned(&sb->sb_mtx) == 0)
> splassert_fail(0, RW_WRITE, __func__);
> } else
> soassertlocked(so);
> Index: sys/sys/systm.h
> ===================================================================
> RCS file: /cvs/src/sys/sys/systm.h,v
> diff -u -p -r1.171 systm.h
> --- sys/sys/systm.h 28 May 2024 12:50:23 -0000 1.171
> +++ sys/sys/systm.h 29 Dec 2024 17:16:17 -0000
> @@ -347,21 +347,22 @@ extern struct rwlock netlock;
> #define NET_ASSERT_UNLOCKED() \
> do { \
> int _s = rw_status(&netlock); \
> - if ((splassert_ctl > 0) && (_s == RW_WRITE)) \
> + if ((atomic_load_int(&splassert_ctl) > 0) && (_s == RW_WRITE)) \
> splassert_fail(0, RW_WRITE, __func__); \
> } while (0)
>
> #define NET_ASSERT_LOCKED() \
> do { \
> int _s = rw_status(&netlock); \
> - if ((splassert_ctl > 0) && (_s != RW_WRITE && _s != RW_READ)) \
> + if ((atomic_load_int(&splassert_ctl) > 0) && \
> + (_s != RW_WRITE && _s != RW_READ)) \
> splassert_fail(RW_READ, _s, __func__); \
> } while (0)
>
> #define NET_ASSERT_LOCKED_EXCLUSIVE() \
> do { \
> int _s = rw_status(&netlock); \
> - if ((splassert_ctl > 0) && (_s != RW_WRITE)) \
> + if ((atomic_load_int(&splassert_ctl) > 0) && (_s != RW_WRITE)) \
> splassert_fail(RW_WRITE, _s, __func__); \
> } while (0)
>
>
>
sysctl(2): unlock KERN_SPLASSERT