From 937c6b27c73e02cd4114f95f5c37ba2c29fadba1 Mon Sep 17 00:00:00 2001 From: Oleg Nesterov Date: Wed, 9 Oct 2019 17:02:30 +0200 Subject: cgroup: freezer: call cgroup_enter_frozen() with preemption disabled in ptrace_stop() ptrace_stop() does preempt_enable_no_resched() to avoid the preemption, but after that cgroup_enter_frozen() does spin_lock/unlock and this adds another preemption point. Reported-and-tested-by: Bruce Ashfield Fixes: 76f969e8948d ("cgroup: cgroup v2 freezer") Cc: stable@vger.kernel.org # v5.2+ Signed-off-by: Oleg Nesterov Acked-by: Roman Gushchin Signed-off-by: Tejun Heo --- kernel/signal.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/signal.c b/kernel/signal.c index c4da1ef56fdf..bcd46f547db3 100644 --- a/kernel/signal.c +++ b/kernel/signal.c @@ -2205,8 +2205,8 @@ static void ptrace_stop(int exit_code, int why, int clear_code, kernel_siginfo_t */ preempt_disable(); read_unlock(&tasklist_lock); - preempt_enable_no_resched(); cgroup_enter_frozen(); + preempt_enable_no_resched(); freezable_schedule(); cgroup_leave_frozen(true); } else { -- cgit From 7541c87c9b7a7e07c84481f37f2c19063b44469b Mon Sep 17 00:00:00 2001 From: Ilya Leoshkevich Date: Mon, 28 Oct 2019 13:29:02 +0100 Subject: bpf: Allow narrow loads of bpf_sysctl fields with offset > 0 "ctx:file_pos sysctl:read read ok narrow" works on s390 by accident: it reads the wrong byte, which happens to have the expected value of 0. Improve the test by seeking to the 4th byte and expecting 4 instead of 0. This makes the latent problem apparent: the test attempts to read the first byte of bpf_sysctl.file_pos, assuming this is the least-significant byte, which is not the case on big-endian machines: a non-zero offset is needed. The point of the test is to verify narrow loads, so we cannot cheat our way out by simply using BPF_W. The existence of the test means that such loads have to be supported, most likely because llvm can generate them. Fix the test by adding a big-endian variant, which uses an offset to access the least-significant byte of bpf_sysctl.file_pos. This reveals the final problem: verifier rejects accesses to bpf_sysctl fields with offset > 0. Such accesses are already allowed for a wide range of structs: __sk_buff, bpf_sock_addr and sk_msg_md to name a few. Extend this support to bpf_sysctl by using bpf_ctx_range instead of offsetof when matching field offsets. Fixes: 7b146cebe30c ("bpf: Sysctl hook") Fixes: e1550bfe0de4 ("bpf: Add file_pos field to bpf_sysctl ctx") Fixes: 9a1027e52535 ("selftests/bpf: Test file_pos field in bpf_sysctl ctx") Signed-off-by: Ilya Leoshkevich Signed-off-by: Alexei Starovoitov Acked-by: Andrey Ignatov Acked-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20191028122902.9763-1-iii@linux.ibm.com --- kernel/bpf/cgroup.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'kernel') diff --git a/kernel/bpf/cgroup.c b/kernel/bpf/cgroup.c index ddd8addcdb5c..a3eaf08e7dd3 100644 --- a/kernel/bpf/cgroup.c +++ b/kernel/bpf/cgroup.c @@ -1311,12 +1311,12 @@ static bool sysctl_is_valid_access(int off, int size, enum bpf_access_type type, return false; switch (off) { - case offsetof(struct bpf_sysctl, write): + case bpf_ctx_range(struct bpf_sysctl, write): if (type != BPF_READ) return false; bpf_ctx_record_field_size(info, size_default); return bpf_ctx_narrow_access_ok(off, size, size_default); - case offsetof(struct bpf_sysctl, file_pos): + case bpf_ctx_range(struct bpf_sysctl, file_pos): if (type == BPF_READ) { bpf_ctx_record_field_size(info, size_default); return bpf_ctx_narrow_access_ok(off, size, size_default); -- cgit From ff1c08e1f74b6864854c39be48aa799a6a2e4d2b Mon Sep 17 00:00:00 2001 From: Björn Töpel Date: Tue, 29 Oct 2019 16:43:07 +0100 Subject: bpf: Change size to u64 for bpf_map_{area_alloc, charge_init}() MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The functions bpf_map_area_alloc() and bpf_map_charge_init() prior this commit passed the size parameter as size_t. In this commit this is changed to u64. All users of these functions avoid size_t overflows on 32-bit systems, by explicitly using u64 when calculating the allocation size and memory charge cost. However, since the result was narrowed by the size_t when passing size and cost to the functions, the overflow handling was in vain. Instead of changing all call sites to size_t and handle overflow at the call site, the parameter is changed to u64 and checked in the functions above. Fixes: d407bd25a204 ("bpf: don't trigger OOM killer under pressure with map alloc") Fixes: c85d69135a91 ("bpf: move memory size checks to bpf_map_charge_init()") Signed-off-by: Björn Töpel Signed-off-by: Daniel Borkmann Reviewed-by: Jakub Kicinski Link: https://lore.kernel.org/bpf/20191029154307.23053-1-bjorn.topel@gmail.com --- kernel/bpf/syscall.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) (limited to 'kernel') diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index 0937719b87e2..ace1cfaa24b6 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -126,7 +126,7 @@ static struct bpf_map *find_and_alloc_map(union bpf_attr *attr) return map; } -void *bpf_map_area_alloc(size_t size, int numa_node) +void *bpf_map_area_alloc(u64 size, int numa_node) { /* We really just want to fail instead of triggering OOM killer * under memory pressure, therefore we set __GFP_NORETRY to kmalloc, @@ -141,6 +141,9 @@ void *bpf_map_area_alloc(size_t size, int numa_node) const gfp_t flags = __GFP_NOWARN | __GFP_ZERO; void *area; + if (size >= SIZE_MAX) + return NULL; + if (size <= (PAGE_SIZE << PAGE_ALLOC_COSTLY_ORDER)) { area = kmalloc_node(size, GFP_USER | __GFP_NORETRY | flags, numa_node); @@ -197,7 +200,7 @@ static void bpf_uncharge_memlock(struct user_struct *user, u32 pages) atomic_long_sub(pages, &user->locked_vm); } -int bpf_map_charge_init(struct bpf_map_memory *mem, size_t size) +int bpf_map_charge_init(struct bpf_map_memory *mem, u64 size) { u32 pages = round_up(size, PAGE_SIZE) >> PAGE_SHIFT; struct user_struct *user; -- cgit From 731dc9df975a5da21237a18c3384f811a7a41cc6 Mon Sep 17 00:00:00 2001 From: Tyler Hicks Date: Mon, 4 Nov 2019 12:22:02 +0100 Subject: cpu/speculation: Uninline and export CPU mitigations helpers A kernel module may need to check the value of the "mitigations=" kernel command line parameter as part of its setup when the module needs to perform software mitigations for a CPU flaw. Uninline and export the helper functions surrounding the cpu_mitigations enum to allow for their usage from a module. Lastly, privatize the enum and cpu_mitigations variable since the value of cpu_mitigations can be checked with the exported helper functions. Signed-off-by: Tyler Hicks Signed-off-by: Paolo Bonzini Signed-off-by: Thomas Gleixner --- kernel/cpu.c | 27 ++++++++++++++++++++++++++- 1 file changed, 26 insertions(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/cpu.c b/kernel/cpu.c index fc28e17940e0..e2cad3ee2ead 100644 --- a/kernel/cpu.c +++ b/kernel/cpu.c @@ -2373,7 +2373,18 @@ void __init boot_cpu_hotplug_init(void) this_cpu_write(cpuhp_state.state, CPUHP_ONLINE); } -enum cpu_mitigations cpu_mitigations __ro_after_init = CPU_MITIGATIONS_AUTO; +/* + * These are used for a global "mitigations=" cmdline option for toggling + * optional CPU mitigations. + */ +enum cpu_mitigations { + CPU_MITIGATIONS_OFF, + CPU_MITIGATIONS_AUTO, + CPU_MITIGATIONS_AUTO_NOSMT, +}; + +static enum cpu_mitigations cpu_mitigations __ro_after_init = + CPU_MITIGATIONS_AUTO; static int __init mitigations_parse_cmdline(char *arg) { @@ -2390,3 +2401,17 @@ static int __init mitigations_parse_cmdline(char *arg) return 0; } early_param("mitigations", mitigations_parse_cmdline); + +/* mitigations=off */ +bool cpu_mitigations_off(void) +{ + return cpu_mitigations == CPU_MITIGATIONS_OFF; +} +EXPORT_SYMBOL_GPL(cpu_mitigations_off); + +/* mitigations=auto,nosmt */ +bool cpu_mitigations_auto_nosmt(void) +{ + return cpu_mitigations == CPU_MITIGATIONS_AUTO_NOSMT; +} +EXPORT_SYMBOL_GPL(cpu_mitigations_auto_nosmt); -- cgit From b0c51f158455e31d5024100cf3580fcd88214b0e Mon Sep 17 00:00:00 2001 From: Jiri Slaby Date: Wed, 30 Oct 2019 08:25:45 +0100 Subject: stacktrace: Don't skip first entry on noncurrent tasks When doing cat /proc//stack, the output is missing the first entry. When the current code walks the stack starting in stack_trace_save_tsk, it skips all scheduler functions (that's OK) plus one more function. But this one function should be skipped only for the 'current' task as it is stack_trace_save_tsk proper. The original code (before the common infrastructure) skipped one function only for the 'current' task -- see save_stack_trace_tsk before 3599fe12a125. So do so also in the new infrastructure now. Fixes: 214d8ca6ee85 ("stacktrace: Provide common infrastructure") Signed-off-by: Jiri Slaby Signed-off-by: Thomas Gleixner Tested-by: Michal Suchanek Acked-by: Josh Poimboeuf Link: https://lkml.kernel.org/r/20191030072545.19462-1-jslaby@suse.cz --- kernel/stacktrace.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) (limited to 'kernel') diff --git a/kernel/stacktrace.c b/kernel/stacktrace.c index 6d1f68b7e528..c9ea7eb2cb1a 100644 --- a/kernel/stacktrace.c +++ b/kernel/stacktrace.c @@ -141,7 +141,8 @@ unsigned int stack_trace_save_tsk(struct task_struct *tsk, unsigned long *store, struct stacktrace_cookie c = { .store = store, .size = size, - .skip = skipnr + 1, + /* skip this function if they are tracing us */ + .skip = skipnr + !!(current == tsk), }; if (!try_get_task_stack(tsk)) @@ -298,7 +299,8 @@ unsigned int stack_trace_save_tsk(struct task_struct *task, struct stack_trace trace = { .entries = store, .max_entries = size, - .skip = skipnr + 1, + /* skip this function if they are tracing us */ + .skip = skipnr + !!(current == task), }; save_stack_trace_tsk(task, &trace); -- cgit From 52338415cf4d4064ae6b8dd972dadbda841da4fa Mon Sep 17 00:00:00 2001 From: Huacai Chen Date: Thu, 24 Oct 2019 11:28:29 +0800 Subject: timekeeping/vsyscall: Update VDSO data unconditionally The update of the VDSO data is depending on __arch_use_vsyscall() returning True. This is a leftover from the attempt to map the features of various architectures 1:1 into generic code. The usage of __arch_use_vsyscall() in the actual vsyscall implementations got dropped and replaced by the requirement for the architecture code to return U64_MAX if the global clocksource is not usable in the VDSO. But the __arch_use_vsyscall() check in the update code stayed which causes the VDSO data to be stale or invalid when an architecture actually implements that function and returns False when the current clocksource is not usable in the VDSO. As a consequence the VDSO implementations of clock_getres(), time(), clock_gettime(CLOCK_.*_COARSE) operate on invalid data and return bogus information. Remove the __arch_use_vsyscall() check from the VDSO update function and update the VDSO data unconditionally. [ tglx: Massaged changelog and removed the now useless implementations in asm-generic/ARM64/MIPS ] Fixes: 44f57d788e7deecb50 ("timekeeping: Provide a generic update_vsyscall() implementation") Signed-off-by: Huacai Chen Signed-off-by: Thomas Gleixner Cc: Andy Lutomirski Cc: Vincenzo Frascino Cc: Arnd Bergmann Cc: Paul Burton Cc: linux-mips@vger.kernel.org Cc: linux-arm-kernel@lists.infradead.org Cc: stable@vger.kernel.org Link: https://lkml.kernel.org/r/1571887709-11447-1-git-send-email-chenhc@lemote.com --- kernel/time/vsyscall.c | 9 +++------ 1 file changed, 3 insertions(+), 6 deletions(-) (limited to 'kernel') diff --git a/kernel/time/vsyscall.c b/kernel/time/vsyscall.c index 4bc37ac3bb05..5ee0f7709410 100644 --- a/kernel/time/vsyscall.c +++ b/kernel/time/vsyscall.c @@ -110,8 +110,7 @@ void update_vsyscall(struct timekeeper *tk) nsec = nsec + tk->wall_to_monotonic.tv_nsec; vdso_ts->sec += __iter_div_u64_rem(nsec, NSEC_PER_SEC, &vdso_ts->nsec); - if (__arch_use_vsyscall(vdata)) - update_vdso_data(vdata, tk); + update_vdso_data(vdata, tk); __arch_update_vsyscall(vdata, tk); @@ -124,10 +123,8 @@ void update_vsyscall_tz(void) { struct vdso_data *vdata = __arch_get_k_vdso_data(); - if (__arch_use_vsyscall(vdata)) { - vdata[CS_HRES_COARSE].tz_minuteswest = sys_tz.tz_minuteswest; - vdata[CS_HRES_COARSE].tz_dsttime = sys_tz.tz_dsttime; - } + vdata[CS_HRES_COARSE].tz_minuteswest = sys_tz.tz_minuteswest; + vdata[CS_HRES_COARSE].tz_dsttime = sys_tz.tz_dsttime; __arch_sync_vdso_data(vdata); } -- cgit From 0ed9ca25894ef673d0259e4bd312d5fa1b9a6591 Mon Sep 17 00:00:00 2001 From: Yi Wang Date: Sat, 19 Oct 2019 17:07:27 +0800 Subject: irq/irqdomain: Update __irq_domain_alloc_fwnode() function documentation A recent commit changed a parameter of __irq_domain_alloc_fwnode(), but did not update the documentation comment. Fix it up. Fixes: b977fcf477c1 ("irqdomain/debugfs: Use PAs to generate fwnode names") Signed-off-by: Yi Wang Signed-off-by: Thomas Gleixner Link: https://lkml.kernel.org/r/1571476047-29463-1-git-send-email-wang.yi59@zte.com.cn --- kernel/irq/irqdomain.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/irq/irqdomain.c b/kernel/irq/irqdomain.c index 132672b74e4b..dd822fd8a7d5 100644 --- a/kernel/irq/irqdomain.c +++ b/kernel/irq/irqdomain.c @@ -51,7 +51,7 @@ EXPORT_SYMBOL_GPL(irqchip_fwnode_ops); * @type: Type of irqchip_fwnode. See linux/irqdomain.h * @name: Optional user provided domain name * @id: Optional user provided id if name != NULL - * @data: Optional user-provided data + * @pa: Optional user-provided physical address * * Allocate a struct irqchip_fwid, and return a poiner to the embedded * fwnode_handle (or NULL on failure). -- cgit From fa729c4df558936b4a1a7b3e2234011f44ede28b Mon Sep 17 00:00:00 2001 From: Christian Brauner Date: Thu, 31 Oct 2019 12:36:08 +0100 Subject: clone3: validate stack arguments Validate the stack arguments and setup the stack depening on whether or not it is growing down or up. Legacy clone() required userspace to know in which direction the stack is growing and pass down the stack pointer appropriately. To make things more confusing microblaze uses a variant of the clone() syscall selected by CONFIG_CLONE_BACKWARDS3 that takes an additional stack_size argument. IA64 has a separate clone2() syscall which also takes an additional stack_size argument. Finally, parisc has a stack that is growing upwards. Userspace therefore has a lot nasty code like the following: #define __STACK_SIZE (8 * 1024 * 1024) pid_t sys_clone(int (*fn)(void *), void *arg, int flags, int *pidfd) { pid_t ret; void *stack; stack = malloc(__STACK_SIZE); if (!stack) return -ENOMEM; #ifdef __ia64__ ret = __clone2(fn, stack, __STACK_SIZE, flags | SIGCHLD, arg, pidfd); #elif defined(__parisc__) /* stack grows up */ ret = clone(fn, stack, flags | SIGCHLD, arg, pidfd); #else ret = clone(fn, stack + __STACK_SIZE, flags | SIGCHLD, arg, pidfd); #endif return ret; } or even crazier variants such as [3]. With clone3() we have the ability to validate the stack. We can check that when stack_size is passed, the stack pointer is valid and the other way around. We can also check that the memory area userspace gave us is fine to use via access_ok(). Furthermore, we probably should not require userspace to know in which direction the stack is growing. It is easy for us to do this in the kernel and I couldn't find the original reasoning behind exposing this detail to userspace. /* Intentional user visible API change */ clone3() was released with 5.3. Currently, it is not documented and very unclear to userspace how the stack and stack_size argument have to be passed. After talking to glibc folks we concluded that trying to change clone3() to setup the stack instead of requiring userspace to do this is the right course of action. Note, that this is an explicit change in user visible behavior we introduce with this patch. If it breaks someone's use-case we will revert! (And then e.g. place the new behavior under an appropriate flag.) Breaking someone's use-case is very unlikely though. First, neither glibc nor musl currently expose a wrapper for clone3(). Second, there is no real motivation for anyone to use clone3() directly since it does not provide features that legacy clone doesn't. New features for clone3() will first happen in v5.5 which is why v5.4 is still a good time to try and make that change now and backport it to v5.3. Searches on [4] did not reveal any packages calling clone3(). [1]: https://lore.kernel.org/r/CAG48ez3q=BeNcuVTKBN79kJui4vC6nw0Bfq6xc-i0neheT17TA@mail.gmail.com [2]: https://lore.kernel.org/r/20191028172143.4vnnjpdljfnexaq5@wittgenstein [3]: https://github.com/systemd/systemd/blob/5238e9575906297608ff802a27e2ff9effa3b338/src/basic/raw-clone.h#L31 [4]: https://codesearch.debian.net Fixes: 7f192e3cd316 ("fork: add clone3") Cc: Kees Cook Cc: Jann Horn Cc: David Howells Cc: Ingo Molnar Cc: Oleg Nesterov Cc: Linus Torvalds Cc: Florian Weimer Cc: Peter Zijlstra Cc: linux-api@vger.kernel.org Cc: linux-kernel@vger.kernel.org Cc: # 5.3 Cc: GNU C Library Signed-off-by: Christian Brauner Acked-by: Arnd Bergmann Acked-by: Aleksa Sarai Link: https://lore.kernel.org/r/20191031113608.20713-1-christian.brauner@ubuntu.com --- kernel/fork.c | 33 ++++++++++++++++++++++++++++++++- 1 file changed, 32 insertions(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/fork.c b/kernel/fork.c index bcdf53125210..55af6931c6ec 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -2561,7 +2561,35 @@ noinline static int copy_clone_args_from_user(struct kernel_clone_args *kargs, return 0; } -static bool clone3_args_valid(const struct kernel_clone_args *kargs) +/** + * clone3_stack_valid - check and prepare stack + * @kargs: kernel clone args + * + * Verify that the stack arguments userspace gave us are sane. + * In addition, set the stack direction for userspace since it's easy for us to + * determine. + */ +static inline bool clone3_stack_valid(struct kernel_clone_args *kargs) +{ + if (kargs->stack == 0) { + if (kargs->stack_size > 0) + return false; + } else { + if (kargs->stack_size == 0) + return false; + + if (!access_ok((void __user *)kargs->stack, kargs->stack_size)) + return false; + +#if !defined(CONFIG_STACK_GROWSUP) && !defined(CONFIG_IA64) + kargs->stack += kargs->stack_size; +#endif + } + + return true; +} + +static bool clone3_args_valid(struct kernel_clone_args *kargs) { /* * All lower bits of the flag word are taken. @@ -2581,6 +2609,9 @@ static bool clone3_args_valid(const struct kernel_clone_args *kargs) kargs->exit_signal) return false; + if (!clone3_stack_valid(kargs)) + return false; + return true; } -- cgit From e3b8b6a0d12cccf772113d6b5c1875192186fbd4 Mon Sep 17 00:00:00 2001 From: Qais Yousef Date: Tue, 5 Nov 2019 11:22:12 +0000 Subject: sched/core: Fix compilation error when cgroup not selected MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit When cgroup is disabled the following compilation error was hit kernel/sched/core.c: In function ‘uclamp_update_active_tasks’: kernel/sched/core.c:1081:23: error: storage size of ‘it’ isn’t known struct css_task_iter it; ^~ kernel/sched/core.c:1084:2: error: implicit declaration of function ‘css_task_iter_start’; did you mean ‘__sg_page_iter_start’? [-Werror=implicit-function-declaration] css_task_iter_start(css, 0, &it); ^~~~~~~~~~~~~~~~~~~ __sg_page_iter_start kernel/sched/core.c:1085:14: error: implicit declaration of function ‘css_task_iter_next’; did you mean ‘__sg_page_iter_next’? [-Werror=implicit-function-declaration] while ((p = css_task_iter_next(&it))) { ^~~~~~~~~~~~~~~~~~ __sg_page_iter_next kernel/sched/core.c:1091:2: error: implicit declaration of function ‘css_task_iter_end’; did you mean ‘get_task_cred’? [-Werror=implicit-function-declaration] css_task_iter_end(&it); ^~~~~~~~~~~~~~~~~ get_task_cred kernel/sched/core.c:1081:23: warning: unused variable ‘it’ [-Wunused-variable] struct css_task_iter it; ^~ cc1: some warnings being treated as errors make[2]: *** [kernel/sched/core.o] Error 1 Fix by protetion uclamp_update_active_tasks() with CONFIG_UCLAMP_TASK_GROUP Fixes: babbe170e053 ("sched/uclamp: Update CPU's refcount on TG's clamp changes") Reported-by: Randy Dunlap Signed-off-by: Qais Yousef Signed-off-by: Peter Zijlstra (Intel) Tested-by: Randy Dunlap Cc: Steven Rostedt Cc: Ingo Molnar Cc: Vincent Guittot Cc: Patrick Bellasi Cc: Mel Gorman Cc: Dietmar Eggemann Cc: Juri Lelli Cc: Ben Segall Link: https://lkml.kernel.org/r/20191105112212.596-1-qais.yousef@arm.com --- kernel/sched/core.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/sched/core.c b/kernel/sched/core.c index dd05a378631a..afd4d8028771 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -1073,6 +1073,7 @@ uclamp_update_active(struct task_struct *p, enum uclamp_id clamp_id) task_rq_unlock(rq, p, &rf); } +#ifdef CONFIG_UCLAMP_TASK_GROUP static inline void uclamp_update_active_tasks(struct cgroup_subsys_state *css, unsigned int clamps) @@ -1091,7 +1092,6 @@ uclamp_update_active_tasks(struct cgroup_subsys_state *css, css_task_iter_end(&it); } -#ifdef CONFIG_UCLAMP_TASK_GROUP static void cpu_util_update_eff(struct cgroup_subsys_state *css); static void uclamp_update_root_tg(void) { -- cgit From 6e2df0581f569038719cf2bc2b3baa3fcc83cab4 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Fri, 8 Nov 2019 11:11:52 +0100 Subject: sched: Fix pick_next_task() vs 'change' pattern race Commit 67692435c411 ("sched: Rework pick_next_task() slow-path") inadvertly introduced a race because it changed a previously unexplored dependency between dropping the rq->lock and sched_class::put_prev_task(). The comments about dropping rq->lock, in for example newidle_balance(), only mentions the task being current and ->on_cpu being set. But when we look at the 'change' pattern (in for example sched_setnuma()): queued = task_on_rq_queued(p); /* p->on_rq == TASK_ON_RQ_QUEUED */ running = task_current(rq, p); /* rq->curr == p */ if (queued) dequeue_task(...); if (running) put_prev_task(...); /* change task properties */ if (queued) enqueue_task(...); if (running) set_next_task(...); It becomes obvious that if we do this after put_prev_task() has already been called on @p, things go sideways. This is exactly what the commit in question allows to happen when it does: prev->sched_class->put_prev_task(rq, prev, rf); if (!rq->nr_running) newidle_balance(rq, rf); The newidle_balance() call will drop rq->lock after we've called put_prev_task() and that allows the above 'change' pattern to interleave and mess up the state. Furthermore, it turns out we lost the RT-pull when we put the last DL task. Fix both problems by extracting the balancing from put_prev_task() and doing a multi-class balance() pass before put_prev_task(). Fixes: 67692435c411 ("sched: Rework pick_next_task() slow-path") Reported-by: Quentin Perret Signed-off-by: Peter Zijlstra (Intel) Tested-by: Quentin Perret Tested-by: Valentin Schneider --- kernel/sched/core.c | 21 +++++++++++++++------ kernel/sched/deadline.c | 40 ++++++++++++++++++++-------------------- kernel/sched/fair.c | 15 ++++++++++++--- kernel/sched/idle.c | 9 ++++++++- kernel/sched/rt.c | 37 +++++++++++++++++++------------------ kernel/sched/sched.h | 30 +++++++++++++++++++++++++++--- kernel/sched/stop_task.c | 18 +++++++++++------- 7 files changed, 112 insertions(+), 58 deletions(-) (limited to 'kernel') diff --git a/kernel/sched/core.c b/kernel/sched/core.c index afd4d8028771..0f2eb3629070 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -3929,13 +3929,22 @@ pick_next_task(struct rq *rq, struct task_struct *prev, struct rq_flags *rf) } restart: +#ifdef CONFIG_SMP /* - * Ensure that we put DL/RT tasks before the pick loop, such that they - * can PULL higher prio tasks when we lower the RQ 'priority'. + * We must do the balancing pass before put_next_task(), such + * that when we release the rq->lock the task is in the same + * state as before we took rq->lock. + * + * We can terminate the balance pass as soon as we know there is + * a runnable task of @class priority or higher. */ - prev->sched_class->put_prev_task(rq, prev, rf); - if (!rq->nr_running) - newidle_balance(rq, rf); + for_class_range(class, prev->sched_class, &idle_sched_class) { + if (class->balance(rq, prev, rf)) + break; + } +#endif + + put_prev_task(rq, prev); for_each_class(class) { p = class->pick_next_task(rq, NULL, NULL); @@ -6201,7 +6210,7 @@ static struct task_struct *__pick_migrate_task(struct rq *rq) for_each_class(class) { next = class->pick_next_task(rq, NULL, NULL); if (next) { - next->sched_class->put_prev_task(rq, next, NULL); + next->sched_class->put_prev_task(rq, next); return next; } } diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c index 2dc48720f189..a8a08030a8f7 100644 --- a/kernel/sched/deadline.c +++ b/kernel/sched/deadline.c @@ -1691,6 +1691,22 @@ static void check_preempt_equal_dl(struct rq *rq, struct task_struct *p) resched_curr(rq); } +static int balance_dl(struct rq *rq, struct task_struct *p, struct rq_flags *rf) +{ + if (!on_dl_rq(&p->dl) && need_pull_dl_task(rq, p)) { + /* + * This is OK, because current is on_cpu, which avoids it being + * picked for load-balance and preemption/IRQs are still + * disabled avoiding further scheduler activity on it and we've + * not yet started the picking loop. + */ + rq_unpin_lock(rq, rf); + pull_dl_task(rq); + rq_repin_lock(rq, rf); + } + + return sched_stop_runnable(rq) || sched_dl_runnable(rq); +} #endif /* CONFIG_SMP */ /* @@ -1758,45 +1774,28 @@ static struct task_struct * pick_next_task_dl(struct rq *rq, struct task_struct *prev, struct rq_flags *rf) { struct sched_dl_entity *dl_se; + struct dl_rq *dl_rq = &rq->dl; struct task_struct *p; - struct dl_rq *dl_rq; WARN_ON_ONCE(prev || rf); - dl_rq = &rq->dl; - - if (unlikely(!dl_rq->dl_nr_running)) + if (!sched_dl_runnable(rq)) return NULL; dl_se = pick_next_dl_entity(rq, dl_rq); BUG_ON(!dl_se); - p = dl_task_of(dl_se); - set_next_task_dl(rq, p); - return p; } -static void put_prev_task_dl(struct rq *rq, struct task_struct *p, struct rq_flags *rf) +static void put_prev_task_dl(struct rq *rq, struct task_struct *p) { update_curr_dl(rq); update_dl_rq_load_avg(rq_clock_pelt(rq), rq, 1); if (on_dl_rq(&p->dl) && p->nr_cpus_allowed > 1) enqueue_pushable_dl_task(rq, p); - - if (rf && !on_dl_rq(&p->dl) && need_pull_dl_task(rq, p)) { - /* - * This is OK, because current is on_cpu, which avoids it being - * picked for load-balance and preemption/IRQs are still - * disabled avoiding further scheduler activity on it and we've - * not yet started the picking loop. - */ - rq_unpin_lock(rq, rf); - pull_dl_task(rq); - rq_repin_lock(rq, rf); - } } /* @@ -2442,6 +2441,7 @@ const struct sched_class dl_sched_class = { .set_next_task = set_next_task_dl, #ifdef CONFIG_SMP + .balance = balance_dl, .select_task_rq = select_task_rq_dl, .migrate_task_rq = migrate_task_rq_dl, .set_cpus_allowed = set_cpus_allowed_dl, diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 682a754ea3e1..22a2fed29054 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -6570,6 +6570,15 @@ static void task_dead_fair(struct task_struct *p) { remove_entity_load_avg(&p->se); } + +static int +balance_fair(struct rq *rq, struct task_struct *prev, struct rq_flags *rf) +{ + if (rq->nr_running) + return 1; + + return newidle_balance(rq, rf) != 0; +} #endif /* CONFIG_SMP */ static unsigned long wakeup_gran(struct sched_entity *se) @@ -6746,7 +6755,7 @@ pick_next_task_fair(struct rq *rq, struct task_struct *prev, struct rq_flags *rf int new_tasks; again: - if (!cfs_rq->nr_running) + if (!sched_fair_runnable(rq)) goto idle; #ifdef CONFIG_FAIR_GROUP_SCHED @@ -6884,7 +6893,7 @@ idle: /* * Account for a descheduled task: */ -static void put_prev_task_fair(struct rq *rq, struct task_struct *prev, struct rq_flags *rf) +static void put_prev_task_fair(struct rq *rq, struct task_struct *prev) { struct sched_entity *se = &prev->se; struct cfs_rq *cfs_rq; @@ -10414,11 +10423,11 @@ const struct sched_class fair_sched_class = { .check_preempt_curr = check_preempt_wakeup, .pick_next_task = pick_next_task_fair, - .put_prev_task = put_prev_task_fair, .set_next_task = set_next_task_fair, #ifdef CONFIG_SMP + .balance = balance_fair, .select_task_rq = select_task_rq_fair, .migrate_task_rq = migrate_task_rq_fair, diff --git a/kernel/sched/idle.c b/kernel/sched/idle.c index 8dad5aa600ea..f65ef1e2f204 100644 --- a/kernel/sched/idle.c +++ b/kernel/sched/idle.c @@ -365,6 +365,12 @@ select_task_rq_idle(struct task_struct *p, int cpu, int sd_flag, int flags) { return task_cpu(p); /* IDLE tasks as never migrated */ } + +static int +balance_idle(struct rq *rq, struct task_struct *prev, struct rq_flags *rf) +{ + return WARN_ON_ONCE(1); +} #endif /* @@ -375,7 +381,7 @@ static void check_preempt_curr_idle(struct rq *rq, struct task_struct *p, int fl resched_curr(rq); } -static void put_prev_task_idle(struct rq *rq, struct task_struct *prev, struct rq_flags *rf) +static void put_prev_task_idle(struct rq *rq, struct task_struct *prev) { } @@ -460,6 +466,7 @@ const struct sched_class idle_sched_class = { .set_next_task = set_next_task_idle, #ifdef CONFIG_SMP + .balance = balance_idle, .select_task_rq = select_task_rq_idle, .set_cpus_allowed = set_cpus_allowed_common, #endif diff --git a/kernel/sched/rt.c b/kernel/sched/rt.c index ebaa4e619684..9b8adc01be3d 100644 --- a/kernel/sched/rt.c +++ b/kernel/sched/rt.c @@ -1469,6 +1469,22 @@ static void check_preempt_equal_prio(struct rq *rq, struct task_struct *p) resched_curr(rq); } +static int balance_rt(struct rq *rq, struct task_struct *p, struct rq_flags *rf) +{ + if (!on_rt_rq(&p->rt) && need_pull_rt_task(rq, p)) { + /* + * This is OK, because current is on_cpu, which avoids it being + * picked for load-balance and preemption/IRQs are still + * disabled avoiding further scheduler activity on it and we've + * not yet started the picking loop. + */ + rq_unpin_lock(rq, rf); + pull_rt_task(rq); + rq_repin_lock(rq, rf); + } + + return sched_stop_runnable(rq) || sched_dl_runnable(rq) || sched_rt_runnable(rq); +} #endif /* CONFIG_SMP */ /* @@ -1552,21 +1568,18 @@ static struct task_struct * pick_next_task_rt(struct rq *rq, struct task_struct *prev, struct rq_flags *rf) { struct task_struct *p; - struct rt_rq *rt_rq = &rq->rt; WARN_ON_ONCE(prev || rf); - if (!rt_rq->rt_queued) + if (!sched_rt_runnable(rq)) return NULL; p = _pick_next_task_rt(rq); - set_next_task_rt(rq, p); - return p; } -static void put_prev_task_rt(struct rq *rq, struct task_struct *p, struct rq_flags *rf) +static void put_prev_task_rt(struct rq *rq, struct task_struct *p) { update_curr_rt(rq); @@ -1578,18 +1591,6 @@ static void put_prev_task_rt(struct rq *rq, struct task_struct *p, struct rq_fla */ if (on_rt_rq(&p->rt) && p->nr_cpus_allowed > 1) enqueue_pushable_task(rq, p); - - if (rf && !on_rt_rq(&p->rt) && need_pull_rt_task(rq, p)) { - /* - * This is OK, because current is on_cpu, which avoids it being - * picked for load-balance and preemption/IRQs are still - * disabled avoiding further scheduler activity on it and we've - * not yet started the picking loop. - */ - rq_unpin_lock(rq, rf); - pull_rt_task(rq); - rq_repin_lock(rq, rf); - } } #ifdef CONFIG_SMP @@ -2366,8 +2367,8 @@ const struct sched_class rt_sched_class = { .set_next_task = set_next_task_rt, #ifdef CONFIG_SMP + .balance = balance_rt, .select_task_rq = select_task_rq_rt, - .set_cpus_allowed = set_cpus_allowed_common, .rq_online = rq_online_rt, .rq_offline = rq_offline_rt, diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h index 0db2c1b3361e..c8870c5bd7df 100644 --- a/kernel/sched/sched.h +++ b/kernel/sched/sched.h @@ -1727,10 +1727,11 @@ struct sched_class { struct task_struct * (*pick_next_task)(struct rq *rq, struct task_struct *prev, struct rq_flags *rf); - void (*put_prev_task)(struct rq *rq, struct task_struct *p, struct rq_flags *rf); + void (*put_prev_task)(struct rq *rq, struct task_struct *p); void (*set_next_task)(struct rq *rq, struct task_struct *p); #ifdef CONFIG_SMP + int (*balance)(struct rq *rq, struct task_struct *prev, struct rq_flags *rf); int (*select_task_rq)(struct task_struct *p, int task_cpu, int sd_flag, int flags); void (*migrate_task_rq)(struct task_struct *p, int new_cpu); @@ -1773,7 +1774,7 @@ struct sched_class { static inline void put_prev_task(struct rq *rq, struct task_struct *prev) { WARN_ON_ONCE(rq->curr != prev); - prev->sched_class->put_prev_task(rq, prev, NULL); + prev->sched_class->put_prev_task(rq, prev); } static inline void set_next_task(struct rq *rq, struct task_struct *next) @@ -1787,8 +1788,12 @@ static inline void set_next_task(struct rq *rq, struct task_struct *next) #else #define sched_class_highest (&dl_sched_class) #endif + +#define for_class_range(class, _from, _to) \ + for (class = (_from); class != (_to); class = class->next) + #define for_each_class(class) \ - for (class = sched_class_highest; class; class = class->next) + for_class_range(class, sched_class_highest, NULL) extern const struct sched_class stop_sched_class; extern const struct sched_class dl_sched_class; @@ -1796,6 +1801,25 @@ extern const struct sched_class rt_sched_class; extern const struct sched_class fair_sched_class; extern const struct sched_class idle_sched_class; +static inline bool sched_stop_runnable(struct rq *rq) +{ + return rq->stop && task_on_rq_queued(rq->stop); +} + +static inline bool sched_dl_runnable(struct rq *rq) +{ + return rq->dl.dl_nr_running > 0; +} + +static inline bool sched_rt_runnable(struct rq *rq) +{ + return rq->rt.rt_queued > 0; +} + +static inline bool sched_fair_runnable(struct rq *rq) +{ + return rq->cfs.nr_running > 0; +} #ifdef CONFIG_SMP diff --git a/kernel/sched/stop_task.c b/kernel/sched/stop_task.c index 7e1cee4e65b2..c0640739e05e 100644 --- a/kernel/sched/stop_task.c +++ b/kernel/sched/stop_task.c @@ -15,6 +15,12 @@ select_task_rq_stop(struct task_struct *p, int cpu, int sd_flag, int flags) { return task_cpu(p); /* stop tasks as never migrate */ } + +static int +balance_stop(struct rq *rq, struct task_struct *prev, struct rq_flags *rf) +{ + return sched_stop_runnable(rq); +} #endif /* CONFIG_SMP */ static void @@ -31,16 +37,13 @@ static void set_next_task_stop(struct rq *rq, struct task_struct *stop) static struct task_struct * pick_next_task_stop(struct rq *rq, struct task_struct *prev, struct rq_flags *rf) { - struct task_struct *stop = rq->stop; - WARN_ON_ONCE(prev || rf); - if (!stop || !task_on_rq_queued(stop)) + if (!sched_stop_runnable(rq)) return NULL; - set_next_task_stop(rq, stop); - - return stop; + set_next_task_stop(rq, rq->stop); + return rq->stop; } static void @@ -60,7 +63,7 @@ static void yield_task_stop(struct rq *rq) BUG(); /* the stop task should never yield, its pointless. */ } -static void put_prev_task_stop(struct rq *rq, struct task_struct *prev, struct rq_flags *rf) +static void put_prev_task_stop(struct rq *rq, struct task_struct *prev) { struct task_struct *curr = rq->curr; u64 delta_exec; @@ -129,6 +132,7 @@ const struct sched_class stop_sched_class = { .set_next_task = set_next_task_stop, #ifdef CONFIG_SMP + .balance = balance_stop, .select_task_rq = select_task_rq_stop, .set_cpus_allowed = set_cpus_allowed_common, #endif -- cgit From 630faf81b3e61bcc90dc6d8b497800657d2752a5 Mon Sep 17 00:00:00 2001 From: Al Viro Date: Sun, 10 Nov 2019 11:53:27 -0500 Subject: cgroup: don't put ERR_PTR() into fc->root the caller of ->get_tree() expects NULL left there on error... Reported-by: Thibaut Sautereau Signed-off-by: Al Viro --- kernel/cgroup/cgroup.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) (limited to 'kernel') diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c index 080561bb8a4b..ef4242e5d4bc 100644 --- a/kernel/cgroup/cgroup.c +++ b/kernel/cgroup/cgroup.c @@ -2119,11 +2119,12 @@ int cgroup_do_get_tree(struct fs_context *fc) nsdentry = kernfs_node_dentry(cgrp->kn, sb); dput(fc->root); - fc->root = nsdentry; if (IS_ERR(nsdentry)) { - ret = PTR_ERR(nsdentry); deactivate_locked_super(sb); + ret = PTR_ERR(nsdentry); + nsdentry = NULL; } + fc->root = nsdentry; } if (!ctx->kfc.new_sb_created) -- cgit From 69924b89687a2923e88cc42144aea27868913d0e Mon Sep 17 00:00:00 2001 From: Al Viro Date: Sat, 2 Nov 2019 13:11:41 -0400 Subject: audit_get_nd(): don't unlock parent too early if the child has been negative and just went positive under us, we want coherent d_is_positive() and ->d_inode. Don't unlock the parent until we'd done that work... Signed-off-by: Al Viro --- kernel/audit_watch.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/audit_watch.c b/kernel/audit_watch.c index 1f31c2f1e6fc..4508d5e0cf69 100644 --- a/kernel/audit_watch.c +++ b/kernel/audit_watch.c @@ -351,12 +351,12 @@ static int audit_get_nd(struct audit_watch *watch, struct path *parent) struct dentry *d = kern_path_locked(watch->path, parent); if (IS_ERR(d)) return PTR_ERR(d); - inode_unlock(d_backing_inode(parent->dentry)); if (d_is_positive(d)) { /* update watch filter fields */ watch->dev = d->d_sb->s_dev; watch->ino = d_backing_inode(d)->i_ino; } + inode_unlock(d_backing_inode(parent->dentry)); dput(d); return 0; } -- cgit From 2f5841349df281ecf8f81cc82d869b8476f0db0b Mon Sep 17 00:00:00 2001 From: Arnd Bergmann Date: Fri, 8 Nov 2019 21:34:24 +0100 Subject: ntp/y2038: Remove incorrect time_t truncation A cast to 'time_t' was accidentally left in place during the conversion of __do_adjtimex() to 64-bit timestamps, so the resulting value is incorrectly truncated. Remove the cast so the 64-bit time gets propagated correctly. Fixes: ead25417f82e ("timex: use __kernel_timex internally") Signed-off-by: Arnd Bergmann Signed-off-by: Thomas Gleixner Cc: stable@vger.kernel.org Link: https://lkml.kernel.org/r/20191108203435.112759-2-arnd@arndb.de --- kernel/time/ntp.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/time/ntp.c b/kernel/time/ntp.c index 65eb796610dc..069ca78fb0bf 100644 --- a/kernel/time/ntp.c +++ b/kernel/time/ntp.c @@ -771,7 +771,7 @@ int __do_adjtimex(struct __kernel_timex *txc, const struct timespec64 *ts, /* fill PPS status fields */ pps_fill_timex(txc); - txc->time.tv_sec = (time_t)ts->tv_sec; + txc->time.tv_sec = ts->tv_sec; txc->time.tv_usec = ts->tv_nsec; if (!(time_status & STA_NANO)) txc->time.tv_usec = ts->tv_nsec / NSEC_PER_USEC; -- cgit From ff51ff84d82aea5a889b85f2b9fb3aa2b8691668 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Tue, 1 Oct 2019 11:18:37 +0200 Subject: sched/core: Avoid spurious lock dependencies While seemingly harmless, __sched_fork() does hrtimer_init(), which, when DEBUG_OBJETS, can end up doing allocations. This then results in the following lock order: rq->lock zone->lock.rlock batched_entropy_u64.lock Which in turn causes deadlocks when we do wakeups while holding that batched_entropy lock -- as the random code does. Solve this by moving __sched_fork() out from under rq->lock. This is safe because nothing there relies on rq->lock, as also evident from the other __sched_fork() callsite. Signed-off-by: Peter Zijlstra (Intel) Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Qian Cai Cc: Thomas Gleixner Cc: akpm@linux-foundation.org Cc: bigeasy@linutronix.de Cc: cl@linux.com Cc: keescook@chromium.org Cc: penberg@kernel.org Cc: rientjes@google.com Cc: thgarnie@google.com Cc: tytso@mit.edu Cc: will@kernel.org Fixes: b7d5dc21072c ("random: add a spinlock_t to struct batched_entropy") Link: https://lkml.kernel.org/r/20191001091837.GK4536@hirez.programming.kicks-ass.net Signed-off-by: Ingo Molnar --- kernel/sched/core.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 0f2eb3629070..33cd25051f3a 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -6019,10 +6019,11 @@ void init_idle(struct task_struct *idle, int cpu) struct rq *rq = cpu_rq(cpu); unsigned long flags; + __sched_fork(0, idle); + raw_spin_lock_irqsave(&idle->pi_lock, flags); raw_spin_lock(&rq->lock); - __sched_fork(0, idle); idle->state = TASK_RUNNING; idle->se.exec_start = sched_clock(); idle->flags |= PF_IDLE; -- cgit From b90f7c9d2198d789709390280a43e0a46345682b Mon Sep 17 00:00:00 2001 From: Vincent Guittot Date: Wed, 30 Oct 2019 12:18:29 +0100 Subject: sched/pelt: Fix update of blocked PELT ordering update_cfs_rq_load_avg() can call cpufreq_update_util() to trigger an update of the frequency. Make sure that RT, DL and IRQ PELT signals have been updated before calling cpufreq. Signed-off-by: Vincent Guittot Signed-off-by: Peter Zijlstra (Intel) Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: dietmar.eggemann@arm.com Cc: dsmythies@telus.net Cc: juri.lelli@redhat.com Cc: mgorman@suse.de Cc: rostedt@goodmis.org Fixes: 371bf4273269 ("sched/rt: Add rt_rq utilization tracking") Fixes: 3727e0e16340 ("sched/dl: Add dl_rq utilization tracking") Fixes: 91c27493e78d ("sched/irq: Add IRQ utilization tracking") Link: https://lkml.kernel.org/r/1572434309-32512-1-git-send-email-vincent.guittot@linaro.org Signed-off-by: Ingo Molnar --- kernel/sched/fair.c | 29 ++++++++++++++++++++--------- 1 file changed, 20 insertions(+), 9 deletions(-) (limited to 'kernel') diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 22a2fed29054..69a81a5709ff 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -7547,6 +7547,19 @@ static void update_blocked_averages(int cpu) rq_lock_irqsave(rq, &rf); update_rq_clock(rq); + /* + * update_cfs_rq_load_avg() can call cpufreq_update_util(). Make sure + * that RT, DL and IRQ signals have been updated before updating CFS. + */ + curr_class = rq->curr->sched_class; + update_rt_rq_load_avg(rq_clock_pelt(rq), rq, curr_class == &rt_sched_class); + update_dl_rq_load_avg(rq_clock_pelt(rq), rq, curr_class == &dl_sched_class); + update_irq_load_avg(rq, 0); + + /* Don't need periodic decay once load/util_avg are null */ + if (others_have_blocked(rq)) + done = false; + /* * Iterates the task_group tree in a bottom up fashion, see * list_add_leaf_cfs_rq() for details. @@ -7574,14 +7587,6 @@ static void update_blocked_averages(int cpu) done = false; } - curr_class = rq->curr->sched_class; - update_rt_rq_load_avg(rq_clock_pelt(rq), rq, curr_class == &rt_sched_class); - update_dl_rq_load_avg(rq_clock_pelt(rq), rq, curr_class == &dl_sched_class); - update_irq_load_avg(rq, 0); - /* Don't need periodic decay once load/util_avg are null */ - if (others_have_blocked(rq)) - done = false; - update_blocked_load_status(rq, !done); rq_unlock_irqrestore(rq, &rf); } @@ -7642,12 +7647,18 @@ static inline void update_blocked_averages(int cpu) rq_lock_irqsave(rq, &rf); update_rq_clock(rq); - update_cfs_rq_load_avg(cfs_rq_clock_pelt(cfs_rq), cfs_rq); + /* + * update_cfs_rq_load_avg() can call cpufreq_update_util(). Make sure + * that RT, DL and IRQ signals have been updated before updating CFS. + */ curr_class = rq->curr->sched_class; update_rt_rq_load_avg(rq_clock_pelt(rq), rq, curr_class == &rt_sched_class); update_dl_rq_load_avg(rq_clock_pelt(rq), rq, curr_class == &dl_sched_class); update_irq_load_avg(rq, 0); + + update_cfs_rq_load_avg(cfs_rq_clock_pelt(cfs_rq), cfs_rq); + update_blocked_load_status(rq, cfs_rq_has_blocked(cfs_rq) || others_have_blocked(rq)); rq_unlock_irqrestore(rq, &rf); } -- cgit From 09f4e8f05d85bfc98fe9227e988a7c1b3ec416ec Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Wed, 6 Nov 2019 12:51:04 +0100 Subject: perf/core: Disallow uncore-cgroup events While discussing uncore event scheduling, I noticed we do not in fact seem to dis-allow making uncore-cgroup events. Such events make no sense what so ever because the cgroup is a CPU local state where uncore counts across a number of CPUs. Disallow them. Signed-off-by: Peter Zijlstra (Intel) Cc: Alexander Shishkin Cc: Arnaldo Carvalho de Melo Cc: David Ahern Cc: Jiri Olsa Cc: Linus Torvalds Cc: Mark Rutland Cc: Namhyung Kim Cc: Stephane Eranian Cc: Thomas Gleixner Cc: Vince Weaver Signed-off-by: Ingo Molnar --- kernel/events/core.c | 9 +++++++++ 1 file changed, 9 insertions(+) (limited to 'kernel') diff --git a/kernel/events/core.c b/kernel/events/core.c index aec8dba2bea4..022a34b66e60 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -10535,6 +10535,15 @@ perf_event_alloc(struct perf_event_attr *attr, int cpu, goto err_ns; } + /* + * Disallow uncore-cgroup events, they don't make sense as the cgroup will + * be different on other CPUs in the uncore mask. + */ + if (pmu->task_ctx_nr == perf_invalid_context && cgroup_fd != -1) { + err = -EINVAL; + goto err_pmu; + } + if (event->attr.aux_output && !(pmu->capabilities & PERF_PMU_CAP_AUX_OUTPUT)) { err = -EOPNOTSUPP; -- cgit From 00496fe5e09e8c8bb115540e7e3470553cd07a5c Mon Sep 17 00:00:00 2001 From: Alexander Shishkin Date: Fri, 1 Nov 2019 17:12:48 +0200 Subject: perf/aux: Fix the aux_output group inheritance fix Commit f733c6b508bc ("perf/core: Fix inheritance of aux_output groups") adds a NULL pointer dereference in case inherit_group() races with perf_release(), which causes the below crash: > BUG: kernel NULL pointer dereference, address: 000000000000010b > #PF: supervisor read access in kernel mode > #PF: error_code(0x0000) - not-present page > PGD 3b203b067 P4D 3b203b067 PUD 3b2040067 PMD 0 > Oops: 0000 [#1] SMP KASAN > CPU: 0 PID: 315 Comm: exclusive-group Tainted: G B 5.4.0-rc3-00181-g72e1839403cb-dirty #878 > RIP: 0010:perf_get_aux_event+0x86/0x270 > Call Trace: > ? __perf_read_group_add+0x3b0/0x3b0 > ? __kasan_check_write+0x14/0x20 > ? __perf_event_init_context+0x154/0x170 > inherit_task_group.isra.0.part.0+0x14b/0x170 > perf_event_init_task+0x296/0x4b0 Fix this by skipping over events that are getting closed, in the inheritance path. Signed-off-by: Alexander Shishkin Signed-off-by: Peter Zijlstra (Intel) Cc: Arnaldo Carvalho de Melo Cc: David Ahern Cc: Jiri Olsa Cc: Linus Torvalds Cc: Mark Rutland Cc: Namhyung Kim Cc: Stephane Eranian Cc: Thomas Gleixner Cc: Vince Weaver Fixes: f733c6b508bc ("perf/core: Fix inheritance of aux_output groups") Link: https://lkml.kernel.org/r/20191101151248.47327-1-alexander.shishkin@linux.intel.com Signed-off-by: Ingo Molnar --- kernel/events/core.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/events/core.c b/kernel/events/core.c index 022a34b66e60..b752bd3aa03b 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -11899,7 +11899,7 @@ static int inherit_group(struct perf_event *parent_event, if (IS_ERR(child_ctr)) return PTR_ERR(child_ctr); - if (sub->aux_event == parent_event && + if (sub->aux_event == parent_event && child_ctr && !perf_get_aux_event(child_ctr, leader)) return -EINVAL; } -- cgit From f25d8ba9e1b204b90fbf55970ea6e68955006068 Mon Sep 17 00:00:00 2001 From: Alexander Shishkin Date: Wed, 30 Oct 2019 15:47:30 +0200 Subject: perf/core: Reattach a misplaced comment A comment is in a wrong place in perf_event_create_kernel_counter(). Fix that. Signed-off-by: Alexander Shishkin Signed-off-by: Peter Zijlstra (Intel) Cc: Arnaldo Carvalho de Melo Cc: David Ahern Cc: Jiri Olsa Cc: Linus Torvalds Cc: Mark Rutland Cc: Namhyung Kim Cc: Stephane Eranian Cc: Thomas Gleixner Cc: Vince Weaver Link: https://lkml.kernel.org/r/20191030134731.5437-2-alexander.shishkin@linux.intel.com Signed-off-by: Ingo Molnar --- kernel/events/core.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-) (limited to 'kernel') diff --git a/kernel/events/core.c b/kernel/events/core.c index b752bd3aa03b..e18d8d34ca77 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -11331,10 +11331,6 @@ perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu, struct perf_event *event; int err; - /* - * Get the target context (task or percpu): - */ - event = perf_event_alloc(attr, cpu, task, NULL, NULL, overflow_handler, context, -1); if (IS_ERR(event)) { @@ -11345,6 +11341,9 @@ perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu, /* Mark owner so we could distinguish it from user events. */ event->owner = TASK_TOMBSTONE; + /* + * Get the target context (task or percpu): + */ ctx = find_get_context(event->pmu, task, event); if (IS_ERR(ctx)) { err = PTR_ERR(ctx); -- cgit From dce5affb94eb54edfff17727a6240a6a5d998666 Mon Sep 17 00:00:00 2001 From: Alexander Shishkin Date: Wed, 30 Oct 2019 15:47:31 +0200 Subject: perf/aux: Disallow aux_output for kernel events Commit ab43762ef0109 ("perf: Allow normal events to output AUX data") added 'aux_output' bit to the attribute structure, which relies on AUX events and grouping, neither of which is supported for the kernel events. This notwithstanding, attempts have been made to use it in the kernel code, suggesting the necessity of an explicit hard -EINVAL. Fix this by rejecting attributes with aux_output set for kernel events. Signed-off-by: Alexander Shishkin Signed-off-by: Peter Zijlstra (Intel) Cc: Arnaldo Carvalho de Melo Cc: David Ahern Cc: Jiri Olsa Cc: Linus Torvalds Cc: Mark Rutland Cc: Namhyung Kim Cc: Stephane Eranian Cc: Thomas Gleixner Cc: Vince Weaver Link: https://lkml.kernel.org/r/20191030134731.5437-3-alexander.shishkin@linux.intel.com Signed-off-by: Ingo Molnar --- kernel/events/core.c | 7 +++++++ 1 file changed, 7 insertions(+) (limited to 'kernel') diff --git a/kernel/events/core.c b/kernel/events/core.c index e18d8d34ca77..7655441065a9 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -11331,6 +11331,13 @@ perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu, struct perf_event *event; int err; + /* + * Grouping is not supported for kernel events, neither is 'AUX', + * make sure the caller's intentions are adjusted. + */ + if (attr->aux_output) + return ERR_PTR(-EINVAL); + event = perf_event_alloc(attr, cpu, task, NULL, NULL, overflow_handler, context, -1); if (IS_ERR(event)) { -- cgit From 697d877849d4b34ab58d7078d6930bad0ef6fc66 Mon Sep 17 00:00:00 2001 From: Alexander Shishkin Date: Tue, 5 Nov 2019 09:57:02 +0200 Subject: perf/core: Consistently fail fork on allocation failures Commit: 313ccb9615948 ("perf: Allocate context task_ctx_data for child event") makes the inherit path skip over the current event in case of task_ctx_data allocation failure. This, however, is inconsistent with allocation failures in perf_event_alloc(), which would abort the fork. Correct this by returning an error code on task_ctx_data allocation failure and failing the fork in that case. Signed-off-by: Alexander Shishkin Signed-off-by: Peter Zijlstra (Intel) Cc: Arnaldo Carvalho de Melo Cc: David Ahern Cc: Jiri Olsa Cc: Jiri Olsa Cc: Linus Torvalds Cc: Mark Rutland Cc: Namhyung Kim Cc: Stephane Eranian Cc: Thomas Gleixner Cc: Vince Weaver Link: https://lkml.kernel.org/r/20191105075702.60319-1-alexander.shishkin@linux.intel.com Signed-off-by: Ingo Molnar --- kernel/events/core.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/events/core.c b/kernel/events/core.c index 7655441065a9..466e333db1f3 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -11802,7 +11802,7 @@ inherit_event(struct perf_event *parent_event, GFP_KERNEL); if (!child_ctx->task_ctx_data) { free_event(child_event); - return NULL; + return ERR_PTR(-ENOMEM); } } -- cgit From d00dbd29814236ad128ff9517e8f7af6b6ef4ba0 Mon Sep 17 00:00:00 2001 From: "Ben Dooks (Codethink)" Date: Wed, 6 Nov 2019 13:25:27 +0000 Subject: perf/core: Fix missing static inline on perf_cgroup_switch() It looks like a "static inline" has been missed in front of the empty definition of perf_cgroup_switch() under certain configurations. Fixes the following sparse warning: kernel/events/core.c:1035:1: warning: symbol 'perf_cgroup_switch' was not declared. Should it be static? Signed-off-by: Ben Dooks (Codethink) Signed-off-by: Peter Zijlstra (Intel) Acked-by: Mark Rutland Cc: Alexander Shishkin Cc: Arnaldo Carvalho de Melo Cc: Arnaldo Carvalho de Melo Cc: David Ahern Cc: Jiri Olsa Cc: Linus Torvalds Cc: Namhyung Kim Cc: Stephane Eranian Cc: Thomas Gleixner Cc: Vince Weaver Link: https://lkml.kernel.org/r/20191106132527.19977-1-ben.dooks@codethink.co.uk Signed-off-by: Ingo Molnar --- kernel/events/core.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/events/core.c b/kernel/events/core.c index 466e333db1f3..00a014670ed0 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -1031,7 +1031,7 @@ perf_cgroup_set_timestamp(struct task_struct *task, { } -void +static inline void perf_cgroup_switch(struct task_struct *task, struct task_struct *next) { } -- cgit From 6e1ff0773f49c7d38e8b4a9df598def6afb9f415 Mon Sep 17 00:00:00 2001 From: Qais Yousef Date: Thu, 14 Nov 2019 21:10:52 +0000 Subject: sched/uclamp: Fix incorrect condition uclamp_update_active() should perform the update when p->uclamp[clamp_id].active is true. But when the logic was inverted in [1], the if condition wasn't inverted correctly too. [1] https://lore.kernel.org/lkml/20190902073836.GO2369@hirez.programming.kicks-ass.net/ Reported-by: Suren Baghdasaryan Signed-off-by: Qais Yousef Signed-off-by: Peter Zijlstra (Intel) Acked-by: Vincent Guittot Cc: Ben Segall Cc: Dietmar Eggemann Cc: Juri Lelli Cc: Linus Torvalds Cc: Mel Gorman Cc: Patrick Bellasi Cc: Peter Zijlstra Cc: Steven Rostedt Cc: Thomas Gleixner Fixes: babbe170e053 ("sched/uclamp: Update CPU's refcount on TG's clamp changes") Link: https://lkml.kernel.org/r/20191114211052.15116-1-qais.yousef@arm.com Signed-off-by: Ingo Molnar --- kernel/sched/core.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 33cd25051f3a..44123b4d14e8 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -1065,7 +1065,7 @@ uclamp_update_active(struct task_struct *p, enum uclamp_id clamp_id) * affecting a valid clamp bucket, the next time it's enqueued, * it will already see the updated clamp bucket value. */ - if (!p->uclamp[clamp_id].active) { + if (p->uclamp[clamp_id].active) { uclamp_rq_dec_id(rq, p, clamp_id); uclamp_rq_inc_id(rq, p, clamp_id); } -- cgit From 7b8474466ed97be458c825f34a85f2c2b84c3f95 Mon Sep 17 00:00:00 2001 From: Dmitry Safonov Date: Thu, 21 Nov 2019 00:03:03 +0000 Subject: time: Zero the upper 32-bits in __kernel_timespec on 32-bit On compat interfaces, the high order bits of nanoseconds should be zeroed out. This is because the application code or the libc do not guarantee zeroing of these. If used without zeroing, kernel might be at risk of using timespec values incorrectly. Originally it was handled correctly, but lost during is_compat_syscall() cleanup. Revert the condition back to check CONFIG_64BIT. Fixes: 98f76206b335 ("compat: Cleanup in_compat_syscall() callers") Reported-by: Ben Hutchings Signed-off-by: Dmitry Safonov Signed-off-by: Thomas Gleixner Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20191121000303.126523-1-dima@arista.com --- kernel/time/time.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/time/time.c b/kernel/time/time.c index 5c54ca632d08..83f403e7a15c 100644 --- a/kernel/time/time.c +++ b/kernel/time/time.c @@ -881,7 +881,8 @@ int get_timespec64(struct timespec64 *ts, ts->tv_sec = kts.tv_sec; /* Zero out the padding for 32 bit systems or in compat mode */ - if (IS_ENABLED(CONFIG_64BIT_TIME) && in_compat_syscall()) + if (IS_ENABLED(CONFIG_64BIT_TIME) && (!IS_ENABLED(CONFIG_64BIT) || + in_compat_syscall())) kts.tv_nsec &= 0xFFFFFFFFUL; ts->tv_nsec = kts.tv_nsec; -- cgit