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Rao" , linux-mm@kvack.org, linux-trace-kernel@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Jinchao Wang Subject: [PATCH 07/17] mm/ksw: add stack probe support Date: Thu, 28 Aug 2025 15:32:40 +0800 Message-ID: <20250828073311.1116593-8-wangjinchao600@gmail.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20250828073311.1116593-1-wangjinchao600@gmail.com> References: <20250828073311.1116593-1-wangjinchao600@gmail.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" 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 { =20 extern bool panic_on_catch; =20 +/* 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 =3D 0; + *watch_len =3D 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 =3D 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 =3D 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 =3D NULL; + + /* Setup entry probe */ + memset(&entry_probe, 0, sizeof(entry_probe)); + entry_probe.symbol_name =3D config->function; + entry_probe.offset =3D config->ip_offset; + entry_probe.post_handler =3D ksw_stack_entry_handler; + probe_config =3D config; + ret =3D 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 =3D ksw_stack_exit_handler; + symbuf =3D probe_config->function; + + ret =3D 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); +} --=20 2.43.0