From df0062b27ebf473b372914a3e3574d93790e2b72 Mon Sep 17 00:00:00 2001 From: Will Deacon Date: Tue, 3 Oct 2017 15:20:50 +0100 Subject: perf/core: Avoid freeing static PMU contexts when PMU is unregistered Since commit: 1fd7e4169954 ("perf/core: Remove perf_cpu_context::unique_pmu") ... when a PMU is unregistered then its associated ->pmu_cpu_context is unconditionally freed. Whilst this is fine for dynamically allocated context types (i.e. those registered using perf_invalid_context), this causes a problem for sharing of static contexts such as perf_{sw,hw}_context, which are used by multiple built-in PMUs and effectively have a global lifetime. Whilst testing the ARM SPE driver, which must use perf_sw_context to support per-task AUX tracing, unregistering the driver as a result of a module unload resulted in: Unable to handle kernel NULL pointer dereference at virtual address 00000038 Internal error: Oops: 96000004 [#1] PREEMPT SMP Modules linked in: [last unloaded: arm_spe_pmu] PC is at ctx_resched+0x38/0xe8 LR is at perf_event_exec+0x20c/0x278 [...] ctx_resched+0x38/0xe8 perf_event_exec+0x20c/0x278 setup_new_exec+0x88/0x118 load_elf_binary+0x26c/0x109c search_binary_handler+0x90/0x298 do_execveat_common.isra.14+0x540/0x618 SyS_execve+0x38/0x48 since the software context has been freed and the ctx.pmu->pmu_disable_count field has been set to NULL. This patch fixes the problem by avoiding the freeing of static PMU contexts altogether. Whilst the sharing of dynamic contexts is questionable, this actually requires the caller to share their context pointer explicitly and so the burden is on them to manage the object lifetime. Reported-by: Kim Phillips Signed-off-by: Will Deacon Signed-off-by: Peter Zijlstra (Intel) Acked-by: Mark Rutland Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Fixes: 1fd7e4169954 ("perf/core: Remove perf_cpu_context::unique_pmu") Link: http://lkml.kernel.org/r/1507040450-7730-1-git-send-email-will.deacon@arm.com Signed-off-by: Ingo Molnar --- kernel/events/core.c | 8 ++++++++ 1 file changed, 8 insertions(+) (limited to 'kernel/events') diff --git a/kernel/events/core.c b/kernel/events/core.c index 6bc21e202ae4..243bfc68d0fe 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -8955,6 +8955,14 @@ static struct perf_cpu_context __percpu *find_pmu_context(int ctxn) static void free_pmu_context(struct pmu *pmu) { + /* + * Static contexts such as perf_sw_context have a global lifetime + * and may be shared between different PMUs. Avoid freeing them + * when a single PMU is going away. + */ + if (pmu->task_ctx_nr > perf_invalid_context) + return; + mutex_lock(&pmus_lock); free_percpu(pmu->pmu_cpu_context); mutex_unlock(&pmus_lock); -- cgit v1.2.3 From e6a5203399d19871021c1fa0eb2a08fc63b67e91 Mon Sep 17 00:00:00 2001 From: "leilei.lin" Date: Fri, 29 Sep 2017 13:54:44 +0800 Subject: perf/core: Fix cgroup time when scheduling descendants Update cgroup time when an event is scheduled in by descendants. Reviewed-and-tested-by: Jiri Olsa Signed-off-by: leilei.lin Signed-off-by: Peter Zijlstra (Intel) Cc: Jiri Olsa Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Stephane Eranian Cc: Thomas Gleixner Cc: acme@kernel.org Cc: alexander.shishkin@linux.intel.com Cc: brendan.d.gregg@gmail.com Cc: yang_oliver@hotmail.com Link: http://lkml.kernel.org/r/CALPjY3mkHiekRkRECzMi9G-bjUQOvOjVBAqxmWkTzc-g+0LwMg@mail.gmail.com Signed-off-by: Ingo Molnar --- kernel/events/core.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel/events') diff --git a/kernel/events/core.c b/kernel/events/core.c index 243bfc68d0fe..9d93db81fa36 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -662,7 +662,7 @@ static inline void update_cgrp_time_from_event(struct perf_event *event) /* * Do not update time when cgroup is not active */ - if (cgrp == event->cgrp) + if (cgroup_is_descendant(cgrp->css.cgroup, event->cgrp->css.cgroup)) __update_cgrp_time(event->cgrp); } -- cgit v1.2.3 From be96b316deff35e119760982c43af74e606fa143 Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Sat, 28 Oct 2017 09:49:37 -0700 Subject: perf/cgroup: Fix perf cgroup hierarchy support The following commit: 864c2357ca89 ("perf/core: Do not set cpuctx->cgrp for unscheduled cgroups") made list_update_cgroup_event() skip setting cpuctx->cgrp if no cgroup event targets %current's cgroup. This breaks perf_event's hierarchical support because events which target one of the ancestors get ignored. Fix it by using cgroup_is_descendant() test instead of equality. Signed-off-by: Tejun Heo Acked-by: Thomas Gleixner Cc: Arnaldo Carvalho de Melo Cc: David Carrillo-Cisneros Cc: Linus Torvalds Cc: Peter Zijlstra Cc: kernel-team@fb.com Cc: stable@vger.kernel.org # v4.9+ Fixes: 864c2357ca89 ("perf/core: Do not set cpuctx->cgrp for unscheduled cgroups") Link: http://lkml.kernel.org/r/20171028164237.GA972780@devbig577.frc2.facebook.com Signed-off-by: Ingo Molnar --- kernel/events/core.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) (limited to 'kernel/events') diff --git a/kernel/events/core.c b/kernel/events/core.c index 9d93db81fa36..10cdb9c26b5d 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -901,9 +901,11 @@ list_update_cgroup_event(struct perf_event *event, cpuctx_entry = &cpuctx->cgrp_cpuctx_entry; /* cpuctx->cgrp is NULL unless a cgroup event is active in this CPU .*/ if (add) { + struct perf_cgroup *cgrp = perf_cgroup_from_task(current, ctx); + list_add(cpuctx_entry, this_cpu_ptr(&cgrp_cpuctx_list)); - if (perf_cgroup_from_task(current, ctx) == event->cgrp) - cpuctx->cgrp = event->cgrp; + if (cgroup_is_descendant(cgrp->css.cgroup, event->cgrp->css.cgroup)) + cpuctx->cgrp = cgrp; } else { list_del(cpuctx_entry); cpuctx->cgrp = NULL; -- cgit v1.2.3 From b24413180f5600bcb3bb70fbed5cf186b60864bd Mon Sep 17 00:00:00 2001 From: Greg Kroah-Hartman Date: Wed, 1 Nov 2017 15:07:57 +0100 Subject: License cleanup: add SPDX GPL-2.0 license identifier to files with no license Many source files in the tree are missing licensing information, which makes it harder for compliance tools to determine the correct license. By default all files without license information are under the default license of the kernel, which is GPL version 2. Update the files which contain no license information with the 'GPL-2.0' SPDX license identifier. The SPDX identifier is a legally binding shorthand, which can be used instead of the full boiler plate text. This patch is based on work done by Thomas Gleixner and Kate Stewart and Philippe Ombredanne. How this work was done: Patches were generated and checked against linux-4.14-rc6 for a subset of the use cases: - file had no licensing information it it. - file was a */uapi/* one with no licensing information in it, - file was a */uapi/* one with existing licensing information, Further patches will be generated in subsequent months to fix up cases where non-standard license headers were used, and references to license had to be inferred by heuristics based on keywords. The analysis to determine which SPDX License Identifier to be applied to a file was done in a spreadsheet of side by side results from of the output of two independent scanners (ScanCode & Windriver) producing SPDX tag:value files created by Philippe Ombredanne. Philippe prepared the base worksheet, and did an initial spot review of a few 1000 files. The 4.13 kernel was the starting point of the analysis with 60,537 files assessed. Kate Stewart did a file by file comparison of the scanner results in the spreadsheet to determine which SPDX license identifier(s) to be applied to the file. She confirmed any determination that was not immediately clear with lawyers working with the Linux Foundation. Criteria used to select files for SPDX license identifier tagging was: - Files considered eligible had to be source code files. - Make and config files were included as candidates if they contained >5 lines of source - File already had some variant of a license header in it (even if <5 lines). All documentation files were explicitly excluded. The following heuristics were used to determine which SPDX license identifiers to apply. - when both scanners couldn't find any license traces, file was considered to have no license information in it, and the top level COPYING file license applied. For non */uapi/* files that summary was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 11139 and resulted in the first patch in this series. If that file was a */uapi/* path one, it was "GPL-2.0 WITH Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 WITH Linux-syscall-note 930 and resulted in the second patch in this series. - if a file had some form of licensing information in it, and was one of the */uapi/* ones, it was denoted with the Linux-syscall-note if any GPL family license was found in the file or had no licensing in it (per prior point). Results summary: SPDX license identifier # files ---------------------------------------------------|------ GPL-2.0 WITH Linux-syscall-note 270 GPL-2.0+ WITH Linux-syscall-note 169 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17 LGPL-2.1+ WITH Linux-syscall-note 15 GPL-1.0+ WITH Linux-syscall-note 14 ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5 LGPL-2.0+ WITH Linux-syscall-note 4 LGPL-2.1 WITH Linux-syscall-note 3 ((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3 ((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1 and that resulted in the third patch in this series. - when the two scanners agreed on the detected license(s), that became the concluded license(s). - when there was disagreement between the two scanners (one detected a license but the other didn't, or they both detected different licenses) a manual inspection of the file occurred. - In most cases a manual inspection of the information in the file resulted in a clear resolution of the license that should apply (and which scanner probably needed to revisit its heuristics). - When it was not immediately clear, the license identifier was confirmed with lawyers working with the Linux Foundation. - If there was any question as to the appropriate license identifier, the file was flagged for further research and to be revisited later in time. In total, over 70 hours of logged manual review was done on the spreadsheet to determine the SPDX license identifiers to apply to the source files by Kate, Philippe, Thomas and, in some cases, confirmation by lawyers working with the Linux Foundation. Kate also obtained a third independent scan of the 4.13 code base from FOSSology, and compared selected files where the other two scanners disagreed against that SPDX file, to see if there was new insights. The Windriver scanner is based on an older version of FOSSology in part, so they are related. Thomas did random spot checks in about 500 files from the spreadsheets for the uapi headers and agreed with SPDX license identifier in the files he inspected. For the non-uapi files Thomas did random spot checks in about 15000 files. In initial set of patches against 4.14-rc6, 3 files were found to have copy/paste license identifier errors, and have been fixed to reflect the correct identifier. Additionally Philippe spent 10 hours this week doing a detailed manual inspection and review of the 12,461 patched files from the initial patch version early this week with: - a full scancode scan run, collecting the matched texts, detected license ids and scores - reviewing anything where there was a license detected (about 500+ files) to ensure that the applied SPDX license was correct - reviewing anything where there was no detection but the patch license was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied SPDX license was correct This produced a worksheet with 20 files needing minor correction. This worksheet was then exported into 3 different .csv files for the different types of files to be modified. These .csv files were then reviewed by Greg. Thomas wrote a script to parse the csv files and add the proper SPDX tag to the file, in the format that the file expected. This script was further refined by Greg based on the output to detect more types of files automatically and to distinguish between header and source .c files (which need different comment types.) Finally Greg ran the script using the .csv files to generate the patches. Reviewed-by: Kate Stewart Reviewed-by: Philippe Ombredanne Reviewed-by: Thomas Gleixner Signed-off-by: Greg Kroah-Hartman --- kernel/events/Makefile | 1 + kernel/events/internal.h | 1 + 2 files changed, 2 insertions(+) (limited to 'kernel/events') diff --git a/kernel/events/Makefile b/kernel/events/Makefile index 2925188f50ea..3c022e33c109 100644 --- a/kernel/events/Makefile +++ b/kernel/events/Makefile @@ -1,3 +1,4 @@ +# SPDX-License-Identifier: GPL-2.0 ifdef CONFIG_FUNCTION_TRACER CFLAGS_REMOVE_core.o = $(CC_FLAGS_FTRACE) endif diff --git a/kernel/events/internal.h b/kernel/events/internal.h index 843e97047335..09b1537ae06c 100644 --- a/kernel/events/internal.h +++ b/kernel/events/internal.h @@ -1,3 +1,4 @@ +/* SPDX-License-Identifier: GPL-2.0 */ #ifndef _KERNEL_EVENTS_INTERNAL_H #define _KERNEL_EVENTS_INTERNAL_H -- cgit v1.2.3