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smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=sk.com; spf=pass smtp.mailfrom=sk.com; arc=none smtp.client-ip=166.125.252.92 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=sk.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=sk.com X-AuditID: a67dfc5b-c45ff70000001609-95-68de3411089a From: Byungchul Park To: linux-kernel@vger.kernel.org Cc: kernel_team@skhynix.com, torvalds@linux-foundation.org, damien.lemoal@opensource.wdc.com, linux-ide@vger.kernel.org, adilger.kernel@dilger.ca, linux-ext4@vger.kernel.org, mingo@redhat.com, peterz@infradead.org, will@kernel.org, tglx@linutronix.de, rostedt@goodmis.org, joel@joelfernandes.org, sashal@kernel.org, daniel.vetter@ffwll.ch, duyuyang@gmail.com, johannes.berg@intel.com, tj@kernel.org, tytso@mit.edu, willy@infradead.org, david@fromorbit.com, amir73il@gmail.com, gregkh@linuxfoundation.org, kernel-team@lge.com, linux-mm@kvack.org, 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ast@kernel.org, ziy@nvidia.com, yuzhao@google.com, baolin.wang@linux.alibaba.com, usamaarif642@gmail.com, joel.granados@kernel.org, richard.weiyang@gmail.com, geert+renesas@glider.be, tim.c.chen@linux.intel.com, linux@treblig.org, alexander.shishkin@linux.intel.com, lillian@star-ark.net, chenhuacai@kernel.org, francesco@valla.it, guoweikang.kernel@gmail.com, link@vivo.com, jpoimboe@kernel.org, masahiroy@kernel.org, brauner@kernel.org, thomas.weissschuh@linutronix.de, oleg@redhat.com, mjguzik@gmail.com, andrii@kernel.org, wangfushuai@baidu.com, linux-doc@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-media@vger.kernel.org, linaro-mm-sig@lists.linaro.org, linux-i2c@vger.kernel.org, linux-arch@vger.kernel.org, linux-modules@vger.kernel.org, rcu@vger.kernel.org, linux-nfs@vger.kernel.org, linux-rt-devel@lists.linux.dev Subject: [PATCH v17 26/47] dept: print staged wait's stacktrace on report Date: Thu, 2 Oct 2025 17:12:26 +0900 Message-Id: <20251002081247.51255-27-byungchul@sk.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20251002081247.51255-1-byungchul@sk.com> References: <20251002081247.51255-1-byungchul@sk.com> X-Brightmail-Tracker: H4sIAAAAAAAAAzWSa0hTcRiH+5/bLjQ4LdGTBtmggq4aWm9g0ac6BUVRfcggW3noLK9tXrIL zNpyXhrLsouaTQsztVrTtLCodGqh5Lw2QV2mjFZuRpnmdNGm+O3h9/7e5/3yCnFpNhksVCSm cMpEebyMEhNi1+LSDdKIIT7sZR8FfyZ0BFifViHw5rcIoLo2E4Pfpn8UFDqKBOBs3g0uewMJ 3ltxcLvAiuCbKQtBz59xCtwmCoyX35BQZd4H9nIHAW2GMgwKnjRg8NTVQcLHoT4S6tVfBGDu b0ZQnefAwTziy+6WDFCg804gUBdNkTD8xUbCpD4ErNevkXDD7UDQ9c6IgaP3KgYtxkB48VaL YED/nYCe/gYElmf1GPTl36fA88jn/ap3CaCqk4CCWR0FudpbBGT+tiPQDETCX9MICW7DBLkz jJ3S6glW2+Wl2BlPPmK1hmrENo2N46ymJp19VTgoYI3mVFZjcZFsTcVa9sFrJ8aaK7MpNsfV g7Ef7swQbMnHg6w9txU7wESLo2K5eEUap9y044SYL+y/gSfPbj/nbWpFauQMz0EiIUNHMLbJ InKBH+ofY36m6DWMzTaN+zmADmVqrjnmOjjdtpzp61zv56X0HkY3bUd+JuhVzGtLicDPEnoL Y8j0oHnnCqbK9G7OI/Ll3cNthJ+ldCSjHdf4bol9nSIR0zvzE59fWMa8r7ARBiQxokWVSKpI 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ItmxkVck6/plJtjHNQx7tmsx21LlpdjSO++prat2CNZkc0pFAadaui5TIK96dw7fG1l7MOp+ gIrQoPQESuAz9HKmrvwyFjdJz2Pevg3jcSfScxjn6X5e3DjdmcS89iyKexq9kSkL+1DcBJ3M 3L53gYpbSKcwuuIx9G/nbMZqb/u7JyFW7/Z3EnGL6BWMNliK6ZDAjCY1okRFXkGuTKFcsUSd Iy/MUxxckpWf60Cxb7IciZy9iULdae2I5iPJZKEn2SsX8WQF6sLcdsTwcUmiMLOhRy4SZssK D3Gq/N2q/UpO3Y5m8gmJWLhpO5cpovfI9nE5HLeXU/3vYvyEGUVItsed8TAyRdg6KTVt57fp 7SXSe9t8FudccSg168SR4NSVGUdzsKVZL6VKc/3wrC/hdaG7UXv2Qk1Q3D/w9HpgtC8YcG03 NS5TCeZItSn+yvQzuRsuZhxLtTrGq/VIJbYb53uT3H0pw4d8q9MrTrKH0xO3hLzbCncl2XpO 3ybvSAi1XCZdgKvUsj8+is8qSQMAAA== X-CFilter-Loop: Reflected Precedence: bulk X-Mailing-List: linux-modules@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Currently, print nothing about what event wakes up in report. However, it makes hard to interpret dept's report. Make it print wait's stacktrace that the event wakes up. Signed-off-by: Byungchul Park --- include/linux/dept.h | 5 ++++ include/linux/sched.h | 2 ++ kernel/dependency/dept.c | 59 ++++++++++++++++++++++++++++++++++------ 3 files changed, 57 insertions(+), 9 deletions(-) diff --git a/include/linux/dept.h b/include/linux/dept.h index 236e4f06e5c8..b6dc4ff19537 100644 --- a/include/linux/dept.h +++ b/include/linux/dept.h @@ -227,6 +227,11 @@ struct dept_ecxt { */ unsigned long event_ip; struct dept_stack *event_stack; + + /* + * wait that this event ttwu + */ + struct dept_stack *ewait_stack; }; }; }; diff --git a/include/linux/sched.h b/include/linux/sched.h index 95b1450f22fa..a01c10f28dfd 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -868,6 +868,7 @@ struct dept_task { const char *stage_w_fn; unsigned long stage_ip; bool stage_timeout; + struct dept_stack *stage_wait_stack; arch_spinlock_t stage_lock; /* @@ -909,6 +910,7 @@ struct dept_task { .stage_w_fn = NULL, \ .stage_ip = 0UL, \ .stage_timeout = false, \ + .stage_wait_stack = NULL, \ .stage_lock = (arch_spinlock_t)__ARCH_SPIN_LOCK_UNLOCKED,\ .missing_ecxt = 0, \ .hardirqs_enabled = false, \ diff --git a/kernel/dependency/dept.c b/kernel/dependency/dept.c index f928c12111fe..1c6eb0a6d0a6 100644 --- a/kernel/dependency/dept.c +++ b/kernel/dependency/dept.c @@ -523,6 +523,7 @@ static void initialize_ecxt(struct dept_ecxt *e) e->enirqf = 0UL; e->event_ip = 0UL; e->event_stack = NULL; + e->ewait_stack = NULL; } SET_CONSTRUCTOR(ecxt, initialize_ecxt); @@ -578,6 +579,8 @@ static void destroy_ecxt(struct dept_ecxt *e) put_stack(e->ecxt_stack); if (e->event_stack) put_stack(e->event_stack); + if (e->ewait_stack) + put_stack(e->ewait_stack); } SET_DESTRUCTOR(ecxt, destroy_ecxt); @@ -794,6 +797,11 @@ static void print_dep(struct dept_dep *d) pr_warn("[E] %s(%s:%d):\n", e_fn, fc_n, fc->sub_id); print_ip_stack(e->event_ip, e->event_stack); + + if (valid_stack(e->ewait_stack)) { + pr_warn("(wait to wake up)\n"); + print_ip_stack(0, e->ewait_stack); + } } if (!irqf) { @@ -807,6 +815,11 @@ static void print_dep(struct dept_dep *d) pr_warn("[E] %s(%s:%d):\n", e_fn, fc_n, fc->sub_id); print_ip_stack(e->event_ip, e->event_stack); + + if (valid_stack(e->ewait_stack)) { + pr_warn("(wait to wake up)\n"); + print_ip_stack(0, e->ewait_stack); + } } } @@ -1657,7 +1670,8 @@ static void add_wait(struct dept_class *c, unsigned long ip, static struct dept_ecxt_held *add_ecxt(struct dept_map *m, struct dept_class *c, unsigned long ip, const char *c_fn, - const char *e_fn, int sub_l) + const char *e_fn, int sub_l, + struct dept_stack *ewait_stack) { struct dept_task *dt = dept_task(); struct dept_ecxt_held *eh; @@ -1691,6 +1705,7 @@ static struct dept_ecxt_held *add_ecxt(struct dept_map *m, e->class = get_class(c); e->ecxt_ip = ip; e->ecxt_stack = ip ? get_current_stack() : NULL; + e->ewait_stack = ewait_stack ? get_stack(ewait_stack) : NULL; e->event_fn = e_fn; e->ecxt_fn = c_fn; @@ -1797,7 +1812,7 @@ static int find_hist_pos(unsigned int wg) static void do_event(struct dept_map *m, struct dept_map *real_m, struct dept_class *c, unsigned int wg, unsigned long ip, - const char *e_fn) + const char *e_fn, struct dept_stack *ewait_stack) { struct dept_task *dt = dept_task(); struct dept_wait_hist *wh; @@ -1825,7 +1840,7 @@ static void do_event(struct dept_map *m, struct dept_map *real_m, */ if (find_ecxt_pos(real_m, c, false) != -1) return; - eh = add_ecxt(m, c, 0UL, NULL, e_fn, 0); + eh = add_ecxt(m, c, 0UL, NULL, e_fn, 0, ewait_stack); if (!eh) return; @@ -2360,7 +2375,8 @@ static void __dept_wait(struct dept_map *m, unsigned long w_f, */ static void __dept_event(struct dept_map *m, struct dept_map *real_m, unsigned long e_f, unsigned long ip, const char *e_fn, - bool sched_map, unsigned int wg) + bool sched_map, unsigned int wg, + struct dept_stack *ewait_stack) { struct dept_class *c; struct dept_key *k; @@ -2382,7 +2398,7 @@ static void __dept_event(struct dept_map *m, struct dept_map *real_m, c = check_new_class(&m->map_key, k, sub_id(m, e), m->name, sched_map); if (c) - do_event(m, real_m, c, wg, ip, e_fn); + do_event(m, real_m, c, wg, ip, e_fn, ewait_stack); } void dept_wait(struct dept_map *m, unsigned long w_f, @@ -2498,6 +2514,9 @@ static void __dept_clean_stage(struct dept_task *dt) dt->stage_w_fn = NULL; dt->stage_ip = 0UL; dt->stage_timeout = false; + if (dt->stage_wait_stack) + put_stack(dt->stage_wait_stack); + dt->stage_wait_stack = NULL; } void dept_clean_stage(void) @@ -2561,6 +2580,14 @@ void dept_request_event_wait_commit(void) wg = next_wgen(); WRITE_ONCE(dt->stage_m.wgen, wg); + + /* + * __schedule() can be hit multiple times between + * dept_stage_wait() and dept_clean_stage(). In that case, + * keep the first stacktrace only. That's enough. + */ + if (!dt->stage_wait_stack) + dt->stage_wait_stack = get_current_stack(); arch_spin_unlock(&dt->stage_lock); __dept_wait(&dt->stage_m, 1UL, ip, w_fn, 0, true, sched_map, timeout); @@ -2579,6 +2606,7 @@ void dept_ttwu_stage_wait(struct task_struct *requestor, unsigned long ip) struct dept_map m; struct dept_map *real_m; bool sched_map; + struct dept_stack *ewait_stack; if (unlikely(!dept_working())) return; @@ -2597,6 +2625,10 @@ void dept_ttwu_stage_wait(struct task_struct *requestor, unsigned long ip) m = dt_req->stage_m; sched_map = dt_req->stage_sched_map; real_m = dt_req->stage_real_m; + ewait_stack = dt_req->stage_wait_stack; + if (ewait_stack) + get_stack(ewait_stack); + __dept_clean_stage(dt_req); arch_spin_unlock(&dt_req->stage_lock); @@ -2607,8 +2639,12 @@ void dept_ttwu_stage_wait(struct task_struct *requestor, unsigned long ip) if (!m.keys) goto exit; - __dept_event(&m, real_m, 1UL, ip, "try_to_wake_up", sched_map, m.wgen); + __dept_event(&m, real_m, 1UL, ip, "try_to_wake_up", sched_map, + m.wgen, ewait_stack); exit: + if (ewait_stack) + put_stack(ewait_stack); + dept_exit(flags); } @@ -2688,7 +2724,7 @@ void dept_map_ecxt_modify(struct dept_map *m, unsigned long e_f, k = m->keys ?: &m->map_key; c = check_new_class(&m->map_key, k, sub_id(m, new_e), m->name, false); - if (c && add_ecxt(m, c, new_ip, new_c_fn, new_e_fn, new_sub_l)) + if (c && add_ecxt(m, c, new_ip, new_c_fn, new_e_fn, new_sub_l, NULL)) goto exit; /* @@ -2740,7 +2776,7 @@ void dept_ecxt_enter(struct dept_map *m, unsigned long e_f, unsigned long ip, k = m->keys ?: &m->map_key; c = check_new_class(&m->map_key, k, sub_id(m, e), m->name, false); - if (c && add_ecxt(m, c, ip, c_fn, e_fn, sub_l)) + if (c && add_ecxt(m, c, ip, c_fn, e_fn, sub_l, NULL)) goto exit; missing_ecxt: dt->missing_ecxt++; @@ -2840,7 +2876,7 @@ void dept_event(struct dept_map *m, unsigned long e_f, flags = dept_enter(); - __dept_event(m, m, e_f, ip, e_fn, false, READ_ONCE(*wg_p)); + __dept_event(m, m, e_f, ip, e_fn, false, READ_ONCE(*wg_p), NULL); /* * Keep the map diabled until the next sleep. @@ -2912,6 +2948,11 @@ void dept_task_exit(struct task_struct *t) dt->stack = NULL; } + if (dt->stage_wait_stack) { + put_stack(dt->stage_wait_stack); + dt->stage_wait_stack = NULL; + } + for (i = 0; i < dt->ecxt_held_pos; i++) { if (dt->ecxt_held[i].class) { put_class(dt->ecxt_held[i].class); -- 2.17.1