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([2a09:bac6:37a8:ec8::179:1b]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-49c5f5972a7sm6417589f8f.21.2026.11.13.10.57.11 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 13 Nov 2026 10:57:11 -0800 (PST) From: Matt Fleming To: Andrew Morton , Marco Elver Cc: Alexander Potapenko , Andrey Konovalov , Dmitry Vyukov , Oscar Salvador , Vlastimil Babka , Caleb Kan , Caleb Kan , linux-mm@kvack.org, linux-kernel@vger.kernel.org, kasan-dev@googlegroups.com, kernel-team@cloudflare.com, Matt Fleming Subject: [PATCH v3 04/10] mm/slub: use stack_depot_fetch_into() for owner tracking Date: Fri, 13 Nov 2026 18:56:56 +0000 Message-ID: <20261113185702.1332171-5-matt@readmodwrite.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20261113185702.1332171-1-matt@readmodwrite.com> References: <20261113185702.1332171-1-matt@readmodwrite.com> X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Caleb Kan SLUB owner tracking stores allocation and free stacks as persistent stack depot handles. Compressed frames must be decompressed before use, so __kmem_obj_info() and the alloc_traces and free_traces debugfs files cannot use stack_depot_fetch(). Use stack_depot_fetch_into() with TRACK_ADDRS_COUNT-sized local arrays. This matches the save-side limit. Keep the existing KS_ADDRS_COUNT copy limit and debugfs formatting unchanged. Continue to copy or print no frames when the fetch returns zero. Signed-off-by: Caleb Kan [mfleming: reworded for compressed frames] Signed-off-by: Matt Fleming --- mm/slub.c | 12 +++++++----- 1 file changed, 7 insertions(+), 5 deletions(-) diff --git a/mm/slub.c b/mm/slub.c index cd671b934719..32e6597a5c03 100644 --- a/mm/slub.c +++ b/mm/slub.c @@ -8328,12 +8328,12 @@ void __kmem_obj_info(struct kmem_obj_info *kpp, void *object, struct slab *slab) #ifdef CONFIG_STACKDEPOT { depot_stack_handle_t handle; - unsigned long *entries; + unsigned long entries[TRACK_ADDRS_COUNT]; unsigned int nr_entries; handle = READ_ONCE(trackp->handle); if (handle) { - nr_entries = stack_depot_fetch(handle, &entries); + nr_entries = stack_depot_fetch_into(handle, entries, ARRAY_SIZE(entries)); for (i = 0; i < KS_ADDRS_COUNT && i < nr_entries; i++) kpp->kp_stack[i] = (void *)entries[i]; } @@ -8341,7 +8341,7 @@ void __kmem_obj_info(struct kmem_obj_info *kpp, void *object, struct slab *slab) trackp = get_track(s, objp, TRACK_FREE); handle = READ_ONCE(trackp->handle); if (handle) { - nr_entries = stack_depot_fetch(handle, &entries); + nr_entries = stack_depot_fetch_into(handle, entries, ARRAY_SIZE(entries)); for (i = 0; i < KS_ADDRS_COUNT && i < nr_entries; i++) kpp->kp_free_stack[i] = (void *)entries[i]; } @@ -10031,12 +10031,14 @@ static int slab_debugfs_show(struct seq_file *seq, void *v) #ifdef CONFIG_STACKDEPOT { depot_stack_handle_t handle; - unsigned long *entries; + unsigned long entries[TRACK_ADDRS_COUNT]; unsigned int nr_entries, j; handle = READ_ONCE(l->handle); if (handle) { - nr_entries = stack_depot_fetch(handle, &entries); + nr_entries = + stack_depot_fetch_into(handle, entries, + ARRAY_SIZE(entries)); seq_puts(seq, "\n"); for (j = 0; j < nr_entries; j++) seq_printf(seq, " %pS\n", (void *)entries[j]); -- 2.43.0