From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id C7DD0ECAAA1 for ; Tue, 30 Aug 2022 21:53:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231984AbiH3VxJ (ORCPT ); Tue, 30 Aug 2022 17:53:09 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60864 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232063AbiH3VwT (ORCPT ); Tue, 30 Aug 2022 17:52:19 -0400 Received: from mail-yb1-xb4a.google.com (mail-yb1-xb4a.google.com [IPv6:2607:f8b0:4864:20::b4a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id DC81B9081F for ; Tue, 30 Aug 2022 14:50:19 -0700 (PDT) Received: by mail-yb1-xb4a.google.com with SMTP id o144-20020a25d796000000b0069b523a4234so717698ybg.17 for ; Tue, 30 Aug 2022 14:50:19 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc; bh=g/YTY0u3yadOEciruM5AsrsoCBr2LdU6F8XKpTCCoXE=; b=W9ws8GQM/90cTDmDN4sijcJEomx0StRc0qnBzUb4l/dKXquUVNd+bkQOSXwJxVHeSR QG60SQEVm6VA17XfZBoKGGzRXcSLpOO21vFhHqE3hmk2c9gf7/HtTYj3kp+LhucXD7zS 32XZBjNXwZuxDqFNmQ7tqseycDiUbS6bSZaQn1dUA4lMpujJGMmrMQrbex/Wc04wsxKu B3eerDWEH6lgqkNOuwBI3NzTboD1OpHxugThISWmfH4bZEx8AfmzAF8N3fNasLdDbLD+ eox1A7oZRZT7QuWta0fKi5W+QGVJWyjQVSgZXf5MPYNZ62sspJg2YTeSPJPL6GlufKLs TtEA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc; bh=g/YTY0u3yadOEciruM5AsrsoCBr2LdU6F8XKpTCCoXE=; b=wBQsk0dEI5bA7m9nbgAb5pnGRZqn4WBaHmJ87ZPKGYmnXPuGvfplHddeH77NWvUIVx Cyo+tcTceIdtT+SkAzYElAWdK3izh5OhU677oW5FqH4L/y6H48M/ISgZ2YMc87V3ifRY Po17Eu1oEW6uQqol4IXd8sN/NxrMMt7lqNPj0EsEBDbi7VPt0R4cjpAtk6h7sqFmYcL2 BuG1jvmNMm6/FVTuWo6+xdzqGoz6+bHmk+Y4PpaF5iZjX+EICkJIA+1UdEhogSfDnN5c lDVaCzUNX44+3o1bs5TgV9wgfawUhIW01+11y43d77wyQ4soVY38PCris19Poy2cye5B Br+A== X-Gm-Message-State: ACgBeo38CpGO+C0ua23zugofrOKB4EUB4XWGZTW43JsPhBzw4PckzJfQ xk4mk9pe08kaMQd8IlnNDwGFJw4790g= X-Google-Smtp-Source: AA6agR7zbyBaHTavSAdE/8JQpYqzjp+0tJKa0FexURSVp+cX649/Bz10TDDbPo8ER0HHDl/6WW+PqHXP88E= X-Received: from surenb-desktop.mtv.corp.google.com ([2620:15c:211:200:a005:55b3:6c26:b3e4]) (user=surenb job=sendgmr) by 2002:a05:6902:100b:b0:695:bd4e:95d6 with SMTP id w11-20020a056902100b00b00695bd4e95d6mr13705955ybt.595.1661896219160; Tue, 30 Aug 2022 14:50:19 -0700 (PDT) Date: Tue, 30 Aug 2022 14:49:10 -0700 In-Reply-To: <20220830214919.53220-1-surenb@google.com> Mime-Version: 1.0 References: <20220830214919.53220-1-surenb@google.com> X-Mailer: git-send-email 2.37.2.672.g94769d06f0-goog Message-ID: <20220830214919.53220-22-surenb@google.com> Subject: [RFC PATCH 21/30] lib: implement context capture support for page and slab allocators From: Suren Baghdasaryan To: akpm@linux-foundation.org Cc: kent.overstreet@linux.dev, mhocko@suse.com, vbabka@suse.cz, hannes@cmpxchg.org, roman.gushchin@linux.dev, mgorman@suse.de, dave@stgolabs.net, willy@infradead.org, liam.howlett@oracle.com, void@manifault.com, peterz@infradead.org, juri.lelli@redhat.com, ldufour@linux.ibm.com, peterx@redhat.com, david@redhat.com, axboe@kernel.dk, mcgrof@kernel.org, masahiroy@kernel.org, nathan@kernel.org, changbin.du@intel.com, ytcoode@gmail.com, vincent.guittot@linaro.org, dietmar.eggemann@arm.com, rostedt@goodmis.org, bsegall@google.com, bristot@redhat.com, vschneid@redhat.com, cl@linux.com, penberg@kernel.org, iamjoonsoo.kim@lge.com, 42.hyeyoo@gmail.com, glider@google.com, elver@google.com, dvyukov@google.com, shakeelb@google.com, songmuchun@bytedance.com, arnd@arndb.de, jbaron@akamai.com, rientjes@google.com, minchan@google.com, kaleshsingh@google.com, surenb@google.com, kernel-team@android.com, linux-mm@kvack.org, iommu@lists.linux.dev, kasan-dev@googlegroups.com, io-uring@vger.kernel.org, linux-arch@vger.kernel.org, xen-devel@lists.xenproject.org, linux-bcache@vger.kernel.org, linux-modules@vger.kernel.org, linux-kernel@vger.kernel.org Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: Implement mechanisms for capturing allocation call context which consists of: - allocation size - pid, tgid and name of the allocating task - allocation timestamp - allocation call stack The patch creates alloc_tags.ctx file which can be written to enable/disable context capture for a specific code tag. Captured context can be obtained by reading alloc_tags.ctx file. Usage example: echo "file include/asm-generic/pgalloc.h line 63 enable" > \ /sys/kernel/debug/alloc_tags.ctx cat alloc_tags.ctx 91.0MiB 212 include/asm-generic/pgalloc.h:63 module:pgtable func:__pte_alloc_one size: 4096 pid: 1551 tgid: 1551 comm: cat ts: 670109646361 call stack: pte_alloc_one+0xfe/0x130 __pte_alloc+0x22/0x90 move_page_tables.part.0+0x994/0xa60 shift_arg_pages+0xa4/0x180 setup_arg_pages+0x286/0x2d0 load_elf_binary+0x4e1/0x18d0 bprm_execve+0x26b/0x660 do_execveat_common.isra.0+0x19d/0x220 __x64_sys_execve+0x2e/0x40 do_syscall_64+0x38/0x90 entry_SYSCALL_64_after_hwframe+0x63/0xcd size: 4096 pid: 1551 tgid: 1551 comm: cat ts: 670109711801 call stack: pte_alloc_one+0xfe/0x130 __do_fault+0x52/0xc0 __handle_mm_fault+0x7d9/0xdd0 handle_mm_fault+0xc0/0x2b0 do_user_addr_fault+0x1c3/0x660 exc_page_fault+0x62/0x150 asm_exc_page_fault+0x22/0x30 ... echo "file include/asm-generic/pgalloc.h line 63 disable" > \ /sys/kernel/debug/alloc_tags.ctx Note that disabling context capture will not clear already captured context but no new context will be captured. Signed-off-by: Suren Baghdasaryan --- include/linux/alloc_tag.h | 28 ++++- include/linux/codetag.h | 3 +- lib/Kconfig.debug | 1 + lib/alloc_tag.c | 239 +++++++++++++++++++++++++++++++++++++- lib/codetag.c | 20 ++-- 5 files changed, 273 insertions(+), 18 deletions(-) diff --git a/include/linux/alloc_tag.h b/include/linux/alloc_tag.h index b3f589afb1c9..66638cbf349a 100644 --- a/include/linux/alloc_tag.h +++ b/include/linux/alloc_tag.h @@ -16,27 +16,41 @@ * an array of these. Embedded codetag utilizes codetag framework. */ struct alloc_tag { - struct codetag ct; + struct codetag_with_ctx ctc; unsigned long last_wrap; struct raw_lazy_percpu_counter call_count; struct raw_lazy_percpu_counter bytes_allocated; } __aligned(8); +static inline struct alloc_tag *ctc_to_alloc_tag(struct codetag_with_ctx *ctc) +{ + return container_of(ctc, struct alloc_tag, ctc); +} + static inline struct alloc_tag *ct_to_alloc_tag(struct codetag *ct) { - return container_of(ct, struct alloc_tag, ct); + return container_of(ct_to_ctc(ct), struct alloc_tag, ctc); } +struct codetag_ctx *alloc_tag_create_ctx(struct alloc_tag *tag, size_t size); +void alloc_tag_free_ctx(struct codetag_ctx *ctx, struct alloc_tag **ptag); +bool alloc_tag_enable_ctx(struct alloc_tag *tag, bool enable); + #define DEFINE_ALLOC_TAG(_alloc_tag) \ static struct alloc_tag _alloc_tag __used __aligned(8) \ - __section("alloc_tags") = { .ct = CODE_TAG_INIT } + __section("alloc_tags") = { .ctc.ct = CODE_TAG_INIT } #define alloc_tag_counter_read(counter) \ __lazy_percpu_counter_read(counter) static inline void __alloc_tag_sub(union codetag_ref *ref, size_t bytes) { - struct alloc_tag *tag = ct_to_alloc_tag(ref->ct); + struct alloc_tag *tag; + + if (is_codetag_ctx_ref(ref)) + alloc_tag_free_ctx(ref->ctx, &tag); + else + tag = ct_to_alloc_tag(ref->ct); __lazy_percpu_counter_add(&tag->call_count, &tag->last_wrap, -1); __lazy_percpu_counter_add(&tag->bytes_allocated, &tag->last_wrap, -bytes); @@ -51,7 +65,11 @@ do { \ static inline void __alloc_tag_add(struct alloc_tag *tag, union codetag_ref *ref, size_t bytes) { - ref->ct = &tag->ct; + if (codetag_ctx_enabled(&tag->ctc)) + ref->ctx = alloc_tag_create_ctx(tag, bytes); + else + ref->ct = &tag->ctc.ct; + __lazy_percpu_counter_add(&tag->call_count, &tag->last_wrap, 1); __lazy_percpu_counter_add(&tag->bytes_allocated, &tag->last_wrap, bytes); } diff --git a/include/linux/codetag.h b/include/linux/codetag.h index 57736ec77b45..a10c5fcbdd20 100644 --- a/include/linux/codetag.h +++ b/include/linux/codetag.h @@ -104,7 +104,8 @@ struct codetag_with_ctx *ct_to_ctc(struct codetag *ct) } void codetag_lock_module_list(struct codetag_type *cttype, bool lock); -struct codetag_iterator codetag_get_ct_iter(struct codetag_type *cttype); +void codetag_init_iter(struct codetag_iterator *iter, + struct codetag_type *cttype); struct codetag *codetag_next_ct(struct codetag_iterator *iter); struct codetag_ctx *codetag_next_ctx(struct codetag_iterator *iter); diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug index 08c97a978906..2790848464f1 100644 --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug @@ -977,6 +977,7 @@ config ALLOC_TAGGING bool select CODE_TAGGING select LAZY_PERCPU_COUNTER + select STACKDEPOT config PAGE_ALLOC_TAGGING bool "Enable page allocation tagging" diff --git a/lib/alloc_tag.c b/lib/alloc_tag.c index 082fbde184ef..50d7bdc2a3c8 100644 --- a/lib/alloc_tag.c +++ b/lib/alloc_tag.c @@ -1,12 +1,75 @@ // SPDX-License-Identifier: GPL-2.0-only #include +#include #include #include #include #include +#include +#include #include +#include #include +#define STACK_BUF_SIZE 1024 + +struct alloc_call_ctx { + struct codetag_ctx ctx; + size_t size; + pid_t pid; + pid_t tgid; + char comm[TASK_COMM_LEN]; + u64 ts_nsec; + depot_stack_handle_t stack_handle; +} __aligned(8); + +static void alloc_tag_ops_free_ctx(struct kref *refcount) +{ + kfree(container_of(kref_to_ctx(refcount), struct alloc_call_ctx, ctx)); +} + +struct codetag_ctx *alloc_tag_create_ctx(struct alloc_tag *tag, size_t size) +{ + struct alloc_call_ctx *ac_ctx; + + /* TODO: use a dedicated kmem_cache */ + ac_ctx = kmalloc(sizeof(struct alloc_call_ctx), GFP_KERNEL); + if (WARN_ON(!ac_ctx)) + return NULL; + + ac_ctx->size = size; + ac_ctx->pid = current->pid; + ac_ctx->tgid = current->tgid; + strscpy(ac_ctx->comm, current->comm, sizeof(ac_ctx->comm)); + ac_ctx->ts_nsec = local_clock(); + ac_ctx->stack_handle = + stack_depot_capture_stack(GFP_NOWAIT | __GFP_NOWARN); + add_ctx(&ac_ctx->ctx, &tag->ctc); + + return &ac_ctx->ctx; +} +EXPORT_SYMBOL_GPL(alloc_tag_create_ctx); + +void alloc_tag_free_ctx(struct codetag_ctx *ctx, struct alloc_tag **ptag) +{ + *ptag = ctc_to_alloc_tag(ctx->ctc); + rem_ctx(ctx, alloc_tag_ops_free_ctx); +} +EXPORT_SYMBOL_GPL(alloc_tag_free_ctx); + +bool alloc_tag_enable_ctx(struct alloc_tag *tag, bool enable) +{ + static bool stack_depot_ready; + + if (enable && !stack_depot_ready) { + stack_depot_init(); + stack_depot_capture_init(); + stack_depot_ready = true; + } + + return codetag_enable_ctx(&tag->ctc, enable); +} + #ifdef CONFIG_DEBUG_FS struct alloc_tag_file_iterator { @@ -50,7 +113,7 @@ static int alloc_tag_file_open(struct inode *inode, struct file *file) return -ENOMEM; codetag_lock_module_list(cttype, true); - iter->ct_iter = codetag_get_ct_iter(cttype); + codetag_init_iter(&iter->ct_iter, cttype); codetag_lock_module_list(cttype, false); seq_buf_init(&iter->buf, iter->rawbuf, sizeof(iter->rawbuf)); file->private_data = iter; @@ -111,14 +174,182 @@ static const struct file_operations alloc_tag_file_ops = { .read = alloc_tag_file_read, }; +static void alloc_tag_ctx_to_text(struct seq_buf *out, struct codetag_ctx *ctx) +{ + struct alloc_call_ctx *ac_ctx; + char *buf; + + ac_ctx = container_of(ctx, struct alloc_call_ctx, ctx); + seq_buf_printf(out, " size: %zu\n", ac_ctx->size); + seq_buf_printf(out, " pid: %d\n", ac_ctx->pid); + seq_buf_printf(out, " tgid: %d\n", ac_ctx->tgid); + seq_buf_printf(out, " comm: %s\n", ac_ctx->comm); + seq_buf_printf(out, " ts: %llu\n", ac_ctx->ts_nsec); + + buf = kmalloc(STACK_BUF_SIZE, GFP_KERNEL); + if (buf) { + int bytes_read = stack_depot_snprint(ac_ctx->stack_handle, buf, + STACK_BUF_SIZE - 1, 8); + buf[bytes_read] = '\0'; + seq_buf_printf(out, " call stack:\n%s\n", buf); + } + kfree(buf); +} + +static ssize_t alloc_tag_ctx_file_read(struct file *file, char __user *ubuf, + size_t size, loff_t *ppos) +{ + struct alloc_tag_file_iterator *iter = file->private_data; + struct codetag_iterator *ct_iter = &iter->ct_iter; + struct user_buf buf = { .buf = ubuf, .size = size }; + struct codetag_ctx *ctx; + struct codetag *prev_ct; + int err = 0; + + codetag_lock_module_list(ct_iter->cttype, true); + while (1) { + err = flush_ubuf(&buf, &iter->buf); + if (err || !buf.size) + break; + + prev_ct = ct_iter->ct; + ctx = codetag_next_ctx(ct_iter); + if (!ctx) + break; + + if (prev_ct != &ctx->ctc->ct) + alloc_tag_to_text(&iter->buf, &ctx->ctc->ct); + alloc_tag_ctx_to_text(&iter->buf, ctx); + } + codetag_lock_module_list(ct_iter->cttype, false); + + return err ? : buf.ret; +} + +#define CTX_CAPTURE_TOKENS() \ + x(disable, 0) \ + x(enable, 0) + +static const char * const ctx_capture_token_strs[] = { +#define x(name, nr_args) #name, + CTX_CAPTURE_TOKENS() +#undef x + NULL +}; + +enum ctx_capture_token { +#define x(name, nr_args) TOK_##name, + CTX_CAPTURE_TOKENS() +#undef x +}; + +static int enable_ctx_capture(struct codetag_type *cttype, + struct codetag_query *query, bool enable) +{ + struct codetag_iterator ct_iter; + struct codetag_with_ctx *ctc; + struct codetag *ct; + unsigned int nfound = 0; + + codetag_lock_module_list(cttype, true); + + codetag_init_iter(&ct_iter, cttype); + while ((ct = codetag_next_ct(&ct_iter))) { + if (!codetag_matches_query(query, ct, ct_iter.cmod, NULL)) + continue; + + ctc = ct_to_ctc(ct); + if (codetag_ctx_enabled(ctc) == enable) + continue; + + if (!alloc_tag_enable_ctx(ctc_to_alloc_tag(ctc), enable)) { + pr_warn("Failed to toggle context capture\n"); + continue; + } + + nfound++; + } + + codetag_lock_module_list(cttype, false); + + return nfound ? 0 : -ENOENT; +} + +static int parse_command(struct codetag_type *cttype, char *buf) +{ + struct codetag_query query = { NULL }; + char *cmd; + int ret; + int tok; + + buf = codetag_query_parse(&query, buf); + if (IS_ERR(buf)) + return PTR_ERR(buf); + + cmd = strsep_no_empty(&buf, " \t\r\n"); + if (!cmd) + return -EINVAL; /* no command */ + + tok = match_string(ctx_capture_token_strs, + ARRAY_SIZE(ctx_capture_token_strs), cmd); + if (tok < 0) + return -EINVAL; /* unknown command */ + + ret = enable_ctx_capture(cttype, &query, tok == TOK_enable); + if (ret < 0) + return ret; + + return 0; +} + +static ssize_t alloc_tag_ctx_file_write(struct file *file, const char __user *ubuf, + size_t len, loff_t *offp) +{ + struct alloc_tag_file_iterator *iter = file->private_data; + char tmpbuf[256]; + + if (len == 0) + return 0; + /* we don't check *offp -- multiple writes() are allowed */ + if (len > sizeof(tmpbuf) - 1) + return -E2BIG; + + if (copy_from_user(tmpbuf, ubuf, len)) + return -EFAULT; + + tmpbuf[len] = '\0'; + parse_command(iter->ct_iter.cttype, tmpbuf); + + *offp += len; + return len; +} + +static const struct file_operations alloc_tag_ctx_file_ops = { + .owner = THIS_MODULE, + .open = alloc_tag_file_open, + .release = alloc_tag_file_release, + .read = alloc_tag_ctx_file_read, + .write = alloc_tag_ctx_file_write, +}; + static int dbgfs_init(struct codetag_type *cttype) { struct dentry *file; + struct dentry *ctx_file; file = debugfs_create_file("alloc_tags", 0444, NULL, cttype, &alloc_tag_file_ops); + if (IS_ERR(file)) + return PTR_ERR(file); + + ctx_file = debugfs_create_file("alloc_tags.ctx", 0666, NULL, cttype, + &alloc_tag_ctx_file_ops); + if (IS_ERR(ctx_file)) { + debugfs_remove(file); + return PTR_ERR(ctx_file); + } - return IS_ERR(file) ? PTR_ERR(file) : 0; + return 0; } #else /* CONFIG_DEBUG_FS */ @@ -129,9 +360,10 @@ static int dbgfs_init(struct codetag_type *) { return 0; } static void alloc_tag_module_unload(struct codetag_type *cttype, struct codetag_module *cmod) { - struct codetag_iterator iter = codetag_get_ct_iter(cttype); + struct codetag_iterator iter; struct codetag *ct; + codetag_init_iter(&iter, cttype); for (ct = codetag_next_ct(&iter); ct; ct = codetag_next_ct(&iter)) { struct alloc_tag *tag = ct_to_alloc_tag(ct); @@ -147,6 +379,7 @@ static int __init alloc_tag_init(void) .section = "alloc_tags", .tag_size = sizeof(struct alloc_tag), .module_unload = alloc_tag_module_unload, + .free_ctx = alloc_tag_ops_free_ctx, }; cttype = codetag_register_type(&desc); diff --git a/lib/codetag.c b/lib/codetag.c index 2762fda5c016..a936d2988c96 100644 --- a/lib/codetag.c +++ b/lib/codetag.c @@ -26,16 +26,14 @@ void codetag_lock_module_list(struct codetag_type *cttype, bool lock) up_read(&cttype->mod_lock); } -struct codetag_iterator codetag_get_ct_iter(struct codetag_type *cttype) +void codetag_init_iter(struct codetag_iterator *iter, + struct codetag_type *cttype) { - struct codetag_iterator iter = { - .cttype = cttype, - .cmod = NULL, - .mod_id = 0, - .ct = NULL, - }; - - return iter; + iter->cttype = cttype; + iter->cmod = NULL; + iter->mod_id = 0; + iter->ct = NULL; + iter->ctx = NULL; } static inline struct codetag *get_first_module_ct(struct codetag_module *cmod) @@ -127,6 +125,10 @@ struct codetag_ctx *codetag_next_ctx(struct codetag_iterator *iter) lockdep_assert_held(&iter->cttype->mod_lock); + /* Move to the first codetag if search just started */ + if (!iter->ct) + codetag_next_ct(iter); + if (!ctx) return next_ctx_from_ct(iter); -- 2.37.2.672.g94769d06f0-goog