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Miller" , Mathieu Desnoyers , linux-trace-kernel@vger.kernel.org Cc: Jinchao Wang Subject: [PATCH v6 12/23] mm/ksw: add entry kprobe and exit fprobe management Date: Tue, 30 Sep 2025 10:43:33 +0800 Message-ID: <20250930024402.1043776-13-wangjinchao600@gmail.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20250930024402.1043776-1-wangjinchao600@gmail.com> References: <20250930024402.1043776-1-wangjinchao600@gmail.com> Precedence: bulk X-Mailing-List: linux-doc@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Provide ksw_stack_init() and ksw_stack_exit() to manage entry and exit probes for the target function from ksw_get_config(). Signed-off-by: Jinchao Wang --- mm/kstackwatch/kstackwatch.h | 4 ++ mm/kstackwatch/stack.c | 101 +++++++++++++++++++++++++++++++++++ 2 files changed, 105 insertions(+) diff --git a/mm/kstackwatch/kstackwatch.h b/mm/kstackwatch/kstackwatch.h index 850fc2b18a9c..4045890e5652 100644 --- a/mm/kstackwatch/kstackwatch.h +++ b/mm/kstackwatch/kstackwatch.h @@ -35,6 +35,10 @@ struct ksw_config { // singleton, only modified in kernel.c const struct ksw_config *ksw_get_config(void); +/* stack management */ +int ksw_stack_init(void); +void ksw_stack_exit(void); + /* watch management */ struct ksw_watchpoint { struct perf_event *__percpu *event; diff --git a/mm/kstackwatch/stack.c b/mm/kstackwatch/stack.c index cec594032515..9f59f41d954c 100644 --- a/mm/kstackwatch/stack.c +++ b/mm/kstackwatch/stack.c @@ -1 +1,102 @@ // SPDX-License-Identifier: GPL-2.0 +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#include +#include +#include +#include +#include + +#include "kstackwatch.h" + +static struct kprobe entry_probe; +static struct fprobe exit_probe; + +static int ksw_stack_prepare_watch(struct pt_regs *regs, + const struct ksw_config *config, + ulong *watch_addr, u16 *watch_len) +{ + /* implement logic will be added in following patches */ + *watch_addr = 0; + *watch_len = 0; + return 0; +} + +static void ksw_stack_entry_handler(struct kprobe *p, struct pt_regs *regs, + unsigned long flags) +{ + struct ksw_ctx *ctx = ¤t->ksw_ctx; + ulong watch_addr; + u16 watch_len; + int ret; + + ret = ksw_watch_get(&ctx->wp); + if (ret) + return; + + ret = ksw_stack_prepare_watch(regs, ksw_get_config(), &watch_addr, + &watch_len); + if (ret) { + ksw_watch_off(ctx->wp); + ctx->wp = NULL; + pr_err("failed to prepare watch target: %d\n", ret); + return; + } + + ret = ksw_watch_on(ctx->wp, watch_addr, watch_len); + if (ret) { + pr_err("failed to watch on depth:%d addr:0x%lx len:%u %d\n", + ksw_get_config()->depth, watch_addr, watch_len, ret); + return; + } + +} + +static void ksw_stack_exit_handler(struct fprobe *fp, unsigned long ip, + unsigned long ret_ip, + struct ftrace_regs *regs, void *data) +{ + struct ksw_ctx *ctx = ¤t->ksw_ctx; + + + if (ctx->wp) { + ksw_watch_off(ctx->wp); + ctx->wp = NULL; + ctx->sp = 0; + } +} + +int ksw_stack_init(void) +{ + int ret; + char *symbuf = NULL; + + memset(&entry_probe, 0, sizeof(entry_probe)); + entry_probe.symbol_name = ksw_get_config()->func_name; + entry_probe.offset = ksw_get_config()->func_offset; + entry_probe.post_handler = ksw_stack_entry_handler; + ret = register_kprobe(&entry_probe); + if (ret) { + pr_err("failed to register kprobe ret %d\n", ret); + return ret; + } + + memset(&exit_probe, 0, sizeof(exit_probe)); + exit_probe.exit_handler = ksw_stack_exit_handler; + symbuf = (char *)ksw_get_config()->func_name; + + ret = register_fprobe_syms(&exit_probe, (const char **)&symbuf, 1); + if (ret < 0) { + pr_err("failed to register fprobe ret %d\n", ret); + unregister_kprobe(&entry_probe); + return ret; + } + + return 0; +} + +void ksw_stack_exit(void) +{ + unregister_fprobe(&exit_probe); + unregister_kprobe(&entry_probe); +} -- 2.43.0