From nobody Sun Jun 14 17:21:05 2026 Received: from 013.lax.mailroute.net (013.lax.mailroute.net [199.89.1.16]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id A775936C0CD for ; Fri, 3 Apr 2026 20:54:14 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=199.89.1.16 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1775249655; cv=none; b=ZhmUZCkw7LltQeBJ5mbTWwvz8dPqCYoDLiysLF34ZR9TgSHvWemZPCt80NA5WUmmnXS7uIcuot4/f78CSiDbEWITGFHGoLd3WDRgHPiJf4n4dFfKNUuq5K9pVsH+FYhLQJ2y6u5tmhxnmzMjDKf2ZJPXQqIXXgjYMz/mDG+1qg8= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1775249655; c=relaxed/simple; bh=XH2IYUtfMatZ+mGfDzGoky7Ba1En8Wrqa9kRAse4RZQ=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version:Content-Type; b=hGkw8OVdOeWlOtbflNjVRd6XGuGlRR2xcPltn2wtz9FX6NYEsQbkETBdwPDv6Wewo8Yfp/n19lmmOxJtuGm2+0tmL5OqHrghHEggKs+e5mdut5H0xTyWyr+odkH6hAdG3UZK3VAiC2gS4kywXRfttn5tU+8blzPl88SxUfx4MHA= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=acm.org; spf=pass smtp.mailfrom=acm.org; dkim=pass (2048-bit key) header.d=acm.org header.i=@acm.org header.b=SC0+/c8s; arc=none smtp.client-ip=199.89.1.16 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=acm.org Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=acm.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=acm.org header.i=@acm.org header.b="SC0+/c8s" Received: from localhost (localhost [127.0.0.1]) by 013.lax.mailroute.net (Postfix) with ESMTP id 4fnWDQ0XGYzlh2fm; Fri, 3 Apr 2026 20:54:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=acm.org; h= content-transfer-encoding:content-type:content-type:mime-version :x-mailer:message-id:date:date:subject:subject:from:from :received:received; s=mr01; t=1775249648; x=1777841649; bh=VBvIO EDQTTUegN0QyJGSr+hU5/ahzIDcycL6RjbQaWQ=; b=SC0+/c8sS6tIiWgmMAdVu BAfF3yJvKxtTk1D4wupsf+6HO+19KQWH/CcyuooKPAkyj/NMya0bULyddIFI5tjx fgqB/Hr1zJBshxaJCPcxo/Zudh2oCI9NVtr095uqB8iOywlN2h0Ez1r0W5w8Qt+S ritnlA0k3sSoe41KWRyeZS7ylG/8v/uuK37SBJPQxuNieB1mASPh5N1UePjFBZgh saO3m0WlNZe+qKILfUXU54nsmQJoicUN7/opFr3bloZePE2DBC2VlVj6ChZr1jK7 izPBYGrBI2IsG4pjG+7U6ODXmBLcBKgtxc4+E/1ZIUCXprkoA8OPOkX0ki3FkEmm Q== X-Virus-Scanned: by MailRoute Received: from 013.lax.mailroute.net ([127.0.0.1]) by localhost (013.lax [127.0.0.1]) (mroute_mailscanner, port 10029) with LMTP id wAAgO1ioq-t6; Fri, 3 Apr 2026 20:54:08 +0000 (UTC) Received: from bvanassche.mtv.corp.google.com (unknown [104.135.180.219]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) (Authenticated sender: bvanassche@acm.org) by 013.lax.mailroute.net (Postfix) with ESMTPSA id 4fnWDG28Lszlgy0r; Fri, 3 Apr 2026 20:54:06 +0000 (UTC) From: Bart Van Assche To: Maarten Lankhorst Cc: Maxime Ripard , linux-kernel@vger.kernel.org, Bart Van Assche , Thomas Zimmermann , =?UTF-8?q?Christian=20K=C3=B6nig?= , Dmitry Baryshkov , Javier Martinez Canillas , David Airlie , Simona Vetter , Nathan Chancellor Subject: [PATCH] drm/fb-helper: Fix a locking bug in an error path Date: Fri, 3 Apr 2026 13:53:54 -0700 Message-ID: <20260403205355.1181984-1-bvanassche@acm.org> X-Mailer: git-send-email 2.53.0.1213.gd9a14994de-goog 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" The name of the function __drm_fb_helper_initial_config_and_unlock() and also the comment above that function make it clear that all code paths in this function should unlock fb_helper->lock before returning. Add a mutex_unlock() call in the only code path where it is missing. This has been detected by the Clang thread-safety analyzer. Cc: Thomas Zimmermann Cc: Christian K=C3=B6nig # radeon Cc: Dmitry Baryshkov # msm Cc: Javier Martinez Canillas Fixes: 63c971af4036 ("drm/fb-helper: Allocate and release fb_info in single= place") Signed-off-by: Bart Van Assche Reviewed-by: Javier Martinez Canillas Reviewed-by: Thomas Zimmermann --- drivers/gpu/drm/drm_fb_helper.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/drivers/gpu/drm/drm_fb_helper.c b/drivers/gpu/drm/drm_fb_helpe= r.c index 05803169bed5..16bfbfb0af16 100644 --- a/drivers/gpu/drm/drm_fb_helper.c +++ b/drivers/gpu/drm/drm_fb_helper.c @@ -1641,8 +1641,10 @@ __drm_fb_helper_initial_config_and_unlock(struct drm= _fb_helper *fb_helper) drm_client_modeset_probe(&fb_helper->client, width, height); =20 info =3D drm_fb_helper_alloc_info(fb_helper); - if (IS_ERR(info)) + if (IS_ERR(info)) { + mutex_unlock(&fb_helper->lock); return PTR_ERR(info); + } =20 ret =3D drm_fb_helper_single_fb_probe(fb_helper); if (ret < 0) {