From nobody Thu Oct 2 20:46:41 2025 Received: from smtp-out2.suse.de (smtp-out2.suse.de [195.135.223.131]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 602E022AE45 for ; Thu, 11 Sep 2025 17:02:51 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=195.135.223.131 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1757610173; cv=none; b=N/JXjoHhNsEf0enKL/oX7N5XLbI9tHRKzc9mIeX8FlwxUQpITvpBjysfVebBE5YEshV1GBYl21vY6XDzs2/94tNQn0r2HhiUIoUb18mkKK8wAdga/ptnYi5NFZDPp3iTVmJz4TWqVHJyXbnSSeAAdqKtzEgfEOpXKinY2lPCXYw= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1757610173; c=relaxed/simple; bh=6tkeaTNyRm1SBHJQKgvKFHCqSVqtEzkC5yHycaSB9t0=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=Hkoi4tH95p4mp13Hv8gXgdOKmazR5mFW95Q1Swp4wgfP1N2h5L5eKZHP+vnNlTpptUJmmkvcjwxZr4Fwi1r5WoYW7x5Cm+9q5yU5VYWaKUTfGl+X+oujW3ry2qHwJh4MarfO1hu+qkDYEm5Xq3YOyKJnBEX7facpro2Fa3FiFAU= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=suse.cz; spf=pass smtp.mailfrom=suse.cz; dkim=pass (1024-bit key) header.d=suse.cz header.i=@suse.cz header.b=caB69UBa; dkim=permerror (0-bit key) header.d=suse.cz header.i=@suse.cz header.b=eciko9ma; dkim=pass (1024-bit key) header.d=suse.cz header.i=@suse.cz header.b=caB69UBa; dkim=permerror (0-bit key) header.d=suse.cz header.i=@suse.cz header.b=eciko9ma; arc=none smtp.client-ip=195.135.223.131 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=suse.cz Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=suse.cz Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=suse.cz header.i=@suse.cz header.b="caB69UBa"; dkim=permerror (0-bit key) header.d=suse.cz header.i=@suse.cz header.b="eciko9ma"; dkim=pass (1024-bit key) header.d=suse.cz header.i=@suse.cz header.b="caB69UBa"; dkim=permerror (0-bit key) header.d=suse.cz header.i=@suse.cz header.b="eciko9ma" Received: from imap1.dmz-prg2.suse.org (unknown [10.150.64.97]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by smtp-out2.suse.de (Postfix) with ESMTPS id 11BE47647F; Thu, 11 Sep 2025 17:02:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_rsa; t=1757610155; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=jRP07fiR2IX4gxo9ENuoZTQhuQ0mAms5suV1861+oXk=; b=caB69UBaTbJw0cyHbpwNyhsojWzldNenRQf7IxQxYYwsRwFbZdTbBFqmXnGnAGylbG5XUg I5a6YRc/oyJW8A5J8RVQ776dTKd4NHj4ur+OL0++IZVMvjqcxkOoHUX9zRiuO8du7yXG5E HxvVaXgq4LODJ7BLPbAebZN/vGYVRTs= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_ed25519; t=1757610155; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=jRP07fiR2IX4gxo9ENuoZTQhuQ0mAms5suV1861+oXk=; b=eciko9ma7alFW2z3yd0wB6yiSLgj3Fo+mGOYT5Imo3INWV5tQGVmCZaGV+oajdOCArOO+C Kot8xIChGaREOEAw== Authentication-Results: smtp-out2.suse.de; none DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_rsa; t=1757610155; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=jRP07fiR2IX4gxo9ENuoZTQhuQ0mAms5suV1861+oXk=; b=caB69UBaTbJw0cyHbpwNyhsojWzldNenRQf7IxQxYYwsRwFbZdTbBFqmXnGnAGylbG5XUg I5a6YRc/oyJW8A5J8RVQ776dTKd4NHj4ur+OL0++IZVMvjqcxkOoHUX9zRiuO8du7yXG5E HxvVaXgq4LODJ7BLPbAebZN/vGYVRTs= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_ed25519; t=1757610155; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=jRP07fiR2IX4gxo9ENuoZTQhuQ0mAms5suV1861+oXk=; b=eciko9ma7alFW2z3yd0wB6yiSLgj3Fo+mGOYT5Imo3INWV5tQGVmCZaGV+oajdOCArOO+C Kot8xIChGaREOEAw== Received: from imap1.dmz-prg2.suse.org (localhost [127.0.0.1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by imap1.dmz-prg2.suse.org (Postfix) with ESMTPS id F0C5C13AD6; Thu, 11 Sep 2025 17:02:34 +0000 (UTC) Received: from dovecot-director2.suse.de ([2a07:de40:b281:106:10:150:64:167]) by imap1.dmz-prg2.suse.org with ESMTPSA id ECiDOqoAw2gUJAAAD6G6ig (envelope-from ); Thu, 11 Sep 2025 17:02:34 +0000 From: Vlastimil Babka Date: Thu, 11 Sep 2025 19:02:35 +0200 Subject: [PATCH 2/6] slab: wrap debug slab validation in validate_slab_ptr() Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20250911-slub-slab-validation-v1-2-8b67eb3b3dc5@suse.cz> References: <20250911-slub-slab-validation-v1-0-8b67eb3b3dc5@suse.cz> In-Reply-To: <20250911-slub-slab-validation-v1-0-8b67eb3b3dc5@suse.cz> To: "Matthew Wilcox (Oracle)" Cc: Harry Yoo , Christoph Lameter , David Rientjes , Roman Gushchin , Andrew Morton , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Vlastimil Babka X-Mailer: b4 0.14.2 X-Spam-Level: X-Spamd-Result: default: False [-4.30 / 50.00]; BAYES_HAM(-3.00)[100.00%]; NEURAL_HAM_LONG(-1.00)[-1.000]; NEURAL_HAM_SHORT(-0.20)[-0.997]; MIME_GOOD(-0.10)[text/plain]; RCVD_VIA_SMTP_AUTH(0.00)[]; FUZZY_RATELIMITED(0.00)[rspamd.com]; ARC_NA(0.00)[]; MIME_TRACE(0.00)[0:+]; RCPT_COUNT_SEVEN(0.00)[9]; MID_RHS_MATCH_FROM(0.00)[]; RCVD_TLS_ALL(0.00)[]; DKIM_SIGNED(0.00)[suse.cz:s=susede2_rsa,suse.cz:s=susede2_ed25519]; FROM_HAS_DN(0.00)[]; TO_DN_SOME(0.00)[]; FROM_EQ_ENVFROM(0.00)[]; TO_MATCH_ENVRCPT_ALL(0.00)[]; RCVD_COUNT_TWO(0.00)[2]; DBL_BLOCKED_OPENRESOLVER(0.00)[suse.cz:email,suse.cz:mid] X-Spam-Flag: NO X-Spam-Score: -4.30 This will make it clear where we currently cast struct slab to folio only to check the slab type, and allow to change the implementation later with memdesc conversion. For now use a struct page based implementation instead of struct folio to be compatible with further upcoming changes. Signed-off-by: Vlastimil Babka Reviewed-by: Harry Yoo --- mm/slub.c | 15 ++++++++++++--- 1 file changed, 12 insertions(+), 3 deletions(-) diff --git a/mm/slub.c b/mm/slub.c index 56143bfd1ae319d384981c810a5ed84af00f4afa..5bbfe4ee8d9846ec9a34584c107= 50388849da3b9 100644 --- a/mm/slub.c +++ b/mm/slub.c @@ -821,6 +821,15 @@ static inline unsigned int get_orig_size(struct kmem_c= ache *s, void *object) return *(unsigned int *)p; } =20 +/* + * For debugging context when we want to check if the struct slab pointer + * appears to be valid. + */ +static bool validate_slab_ptr(struct slab *slab) +{ + return PageSlab(slab_page(slab)); +} + #ifdef CONFIG_SLUB_DEBUG static unsigned long object_map[BITS_TO_LONGS(MAX_OBJS_PER_PAGE)]; static DEFINE_SPINLOCK(object_map_lock); @@ -1453,7 +1462,7 @@ static int check_slab(struct kmem_cache *s, struct sl= ab *slab) { int maxobj; =20 - if (!folio_test_slab(slab_folio(slab))) { + if (!validate_slab_ptr(slab)) { slab_err(s, slab, "Not a valid slab page"); return 0; } @@ -1653,7 +1662,7 @@ static noinline bool alloc_debug_processing(struct km= em_cache *s, return true; =20 bad: - if (folio_test_slab(slab_folio(slab))) { + if (validate_slab_ptr(slab)) { /* * If this is a slab page then lets do the best we can * to avoid issues in the future. Marking all objects @@ -2818,7 +2827,7 @@ static void *alloc_single_from_partial(struct kmem_ca= che *s, slab->inuse++; =20 if (!alloc_debug_processing(s, slab, object, orig_size)) { - if (folio_test_slab(slab_folio(slab))) + if (validate_slab_ptr(slab)) remove_partial(n, slab); return NULL; } --=20 2.51.0