From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from 003.mia.mailroute.net (003.mia.mailroute.net [199.89.3.6]) (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 61C5E1F63CD for ; Tue, 7 Oct 2025 21:48:27 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=199.89.3.6 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1759873709; cv=none; b=MDR+GzlTB5cS8hYMxBJ0Rmbri6QnxL/yd7V/wC3/7nC+M1391g6y2LuqhhPViwajZRgUYHTGsI1FUheWArHxbxzexH3mSpF2coxsVfDCPDHJcsCBBy0l1CIQSkicR6SJTpCIkltTSX96l9g/KBiRO8iCvlb/EfDeu8FWcJYhUkM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1759873709; c=relaxed/simple; bh=aHSOMWISwHQa4yM9lAmfrDtmUaqAzv+6gd1Ofi39Rw8=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=BDcROW2ML9UhjxTxv9f0DW4vHouNbrKv1yRu1IVV7bsrU6B6RCDOLZbQgt80cVNbaihJjbt4LP6yl414hHAQtX/XqiufufPGpEfe1GztdD5eln2JiKjD3ynsRVb9RM6GSuDt2W3kBBcIkfqWKO2eH5x5J1CCIEz+foerITrim6U= 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=a5+OOTzg; arc=none smtp.client-ip=199.89.3.6 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="a5+OOTzg" Received: from localhost (localhost [127.0.0.1]) by 003.mia.mailroute.net (Postfix) with ESMTP id 4ch8rz7454zlgqVx; Tue, 7 Oct 2025 21:48:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=acm.org; h= content-transfer-encoding:mime-version:x-mailer:message-id:date :date:subject:subject:from:from:received:received; s=mr01; t= 1759873698; x=1762465699; bh=v2izTBZE/hUlM6ag5GWowe5UTGqRk8b+LgW kcda96ZE=; b=a5+OOTzgfdPPb9dg1PVtJeJBvfmFS+Unuu2Rp7sZJyw3CipB8Lz ZOgzfltiSJ59bP2wX1y9cMH2Hnga+OriLlBTQJyIj3N6NLLxKdfuXAT6fkilLNqY BTDiMDS1N9IWixsMoUafwxajwKtc+4ztsv0YAYiAPXbFsGmgtNavWrc5dNKqpTm6 VvUEH+kQIic4vRMMWR/Hi5RlvdL4iFU5+U4sMeHFGMhsuU9tlZ9nyY9/opc8Q0mJ ofmkD21F+5/+ECQ3eEz4EPzktJ2F5KfWjqVlbZHr/2RezN+2Q+++bkYJq/qryv4s A8kF356shc0ocZ7kJl9R7rHFNyEuaY4DN8g== X-Virus-Scanned: by MailRoute Received: from 003.mia.mailroute.net ([127.0.0.1]) by localhost (003.mia [127.0.0.1]) (mroute_mailscanner, port 10029) with LMTP id oZQvKAFZsVHt; Tue, 7 Oct 2025 21:48:18 +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 003.mia.mailroute.net (Postfix) with ESMTPSA id 4ch8rt1D9DzlgqW3; Tue, 7 Oct 2025 21:48:13 +0000 (UTC) From: Bart Van Assche To: "Martin K . Petersen" Cc: linux-scsi@vger.kernel.org, Bart Van Assche , Sebastian Reichel , Ming Lei , Jens Axboe , "James E.J. Bottomley" Subject: [PATCH] scsi: core: Fix a regression triggered by scsi_host_busy() Date: Tue, 7 Oct 2025 14:48:00 -0700 Message-ID: <20251007214800.1678255-1-bvanassche@acm.org> X-Mailer: git-send-email 2.51.0.710.ga91ca5db03-goog Precedence: bulk X-Mailing-List: linux-scsi@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Commit 995412e23bb2 ("blk-mq: Replace tags->lock with SRCU for tag iterators") introduced the following regression: Call trace: __srcu_read_lock+0x30/0x80 (P) blk_mq_tagset_busy_iter+0x44/0x300 scsi_host_busy+0x38/0x70 ufshcd_print_host_state+0x34/0x1bc ufshcd_link_startup.constprop.0+0xe4/0x2e0 ufshcd_init+0x944/0xf80 ufshcd_pltfrm_init+0x504/0x820 ufs_rockchip_probe+0x2c/0x88 platform_probe+0x5c/0xa4 really_probe+0xc0/0x38c __driver_probe_device+0x7c/0x150 driver_probe_device+0x40/0x120 __driver_attach+0xc8/0x1e0 bus_for_each_dev+0x7c/0xdc driver_attach+0x24/0x30 bus_add_driver+0x110/0x230 driver_register+0x68/0x130 __platform_driver_register+0x20/0x2c ufs_rockchip_pltform_init+0x1c/0x28 do_one_initcall+0x60/0x1e0 kernel_init_freeable+0x248/0x2c4 kernel_init+0x20/0x140 ret_from_fork+0x10/0x20 Fix this regression by making scsi_host_busy() check whether the SCSI host tag set has already been initialized. tag_set->ops is set by scsi_mq_setup_tags() just before blk_mq_alloc_tag_set() is called. This fix is based on the assumption that scsi_host_busy() and scsi_mq_setup_tags() calls are serialized. This is the case in the UFS driver. Reported-by: Sebastian Reichel Closes: https://lore.kernel.org/linux-block/pnezafputodmqlpumwfbn644ohjyb= ouveehcjhz2hmhtcf2rka@sdhoiivync4y/ Cc: Ming Lei Cc: Jens Axboe Signed-off-by: Bart Van Assche --- drivers/scsi/hosts.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/drivers/scsi/hosts.c b/drivers/scsi/hosts.c index cc5d05dc395c..17173239301e 100644 --- a/drivers/scsi/hosts.c +++ b/drivers/scsi/hosts.c @@ -611,8 +611,9 @@ int scsi_host_busy(struct Scsi_Host *shost) { int cnt =3D 0; =20 - blk_mq_tagset_busy_iter(&shost->tag_set, - scsi_host_check_in_flight, &cnt); + if (shost->tag_set.ops) + blk_mq_tagset_busy_iter(&shost->tag_set, + scsi_host_check_in_flight, &cnt); return cnt; } EXPORT_SYMBOL(scsi_host_busy);