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Rao" , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org, "H. Peter Anvin" , Peter Zijlstra , Arnaldo Carvalho de Melo , Namhyung Kim , Mark Rutland , Alexander Shishkin , Jiri Olsa , Ian Rogers , Adrian Hunter , "Liang, Kan" , David Hildenbrand , Lorenzo Stoakes , "Liam R. Howlett" , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , linux-perf-users@vger.kernel.org, linux-mm@kvack.org, linux-trace-kernel@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Jinchao Wang Subject: [PATCH v2 08/18] mm/ksw: add stack probe support Date: Thu, 4 Sep 2025 08:21:05 +0800 Message-ID: <20250904002126.1514566-9-wangjinchao600@gmail.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20250904002126.1514566-1-wangjinchao600@gmail.com> References: <20250904002126.1514566-1-wangjinchao600@gmail.com> Precedence: bulk X-Mailing-List: linux-perf-users@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Introduce stack management for KStackWatch using kprobes and fprobes to enable dynamic watch switching: - Entry: prepare target address/length and enable watch - Exit: disable watch Signed-off-by: Jinchao Wang --- mm/kstackwatch/kstackwatch.h | 4 ++ mm/kstackwatch/stack.c | 91 ++++++++++++++++++++++++++++++++++++ 2 files changed, 95 insertions(+) diff --git a/mm/kstackwatch/kstackwatch.h b/mm/kstackwatch/kstackwatch.h index 13ef8c79f855..bc8664af4fa6 100644 --- a/mm/kstackwatch/kstackwatch.h +++ b/mm/kstackwatch/kstackwatch.h @@ -38,6 +38,10 @@ struct ksw_config { extern bool panic_on_catch; +/* stack management */ +int ksw_stack_init(struct ksw_config *config); +void ksw_stack_exit(void); + /* watch management */ int ksw_watch_init(struct ksw_config *config); void ksw_watch_exit(void); diff --git a/mm/kstackwatch/stack.c b/mm/kstackwatch/stack.c index cec594032515..3b72177315cc 100644 --- a/mm/kstackwatch/stack.c +++ b/mm/kstackwatch/stack.c @@ -1 +1,92 @@ // SPDX-License-Identifier: GPL-2.0 + +#include +#include +#include +#include + +#include "kstackwatch.h" + +struct ksw_config *probe_config; + +/* prepare watch_addr and watch_len for watch */ +static int ksw_stack_prepare_watch(struct pt_regs *regs, + struct ksw_config *config, u64 *watch_addr, + u64 *watch_len) +{ + /* TODO: implement logic */ + *watch_addr = 0; + *watch_len = 0; + return 0; +} + +static struct kprobe entry_probe; +static struct fprobe exit_probe_fprobe; + +static void ksw_stack_entry_handler(struct kprobe *p, struct pt_regs *regs, + unsigned long flags) +{ + int ret; + u64 watch_addr; + u64 watch_len; + + ret = ksw_stack_prepare_watch(regs, probe_config, &watch_addr, + &watch_len); + if (ret) { + pr_err("KSW: failed to prepare watch target: %d\n", ret); + return; + } + + ret = ksw_watch_on(watch_addr, watch_len); + if (ret) { + pr_err("KSW: failed to watch on addr:0x%llx len:%llx %d\n", + 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) +{ + ksw_watch_off(); +} + +int ksw_stack_init(struct ksw_config *config) +{ + int ret; + char *symbuf = NULL; + + /* Setup entry probe */ + memset(&entry_probe, 0, sizeof(entry_probe)); + entry_probe.symbol_name = config->function; + entry_probe.offset = config->ip_offset; + entry_probe.post_handler = ksw_stack_entry_handler; + probe_config = config; + ret = register_kprobe(&entry_probe); + if (ret < 0) { + pr_err("KSW: Failed to register kprobe ret %d\n", ret); + return ret; + } + + /* Setup exit probe */ + memset(&exit_probe_fprobe, 0, sizeof(exit_probe_fprobe)); + exit_probe_fprobe.exit_handler = ksw_stack_exit_handler; + symbuf = probe_config->function; + + ret = register_fprobe_syms(&exit_probe_fprobe, (const char **)&symbuf, + 1); + if (ret < 0) { + pr_err("KSW: register_fprobe_syms fail %d\n", ret); + unregister_kprobe(&entry_probe); + return ret; + } + + return 0; +} + +void ksw_stack_exit(void) +{ + unregister_fprobe(&exit_probe_fprobe); + unregister_kprobe(&entry_probe); +} -- 2.43.0