From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 28E392459C9; Tue, 9 Sep 2025 09:00:45 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1757408446; cv=none; b=B2+ZKzL+Ev7lNLj4evX2Y4TA0b9c+0gUg1V44CVo1YOr30EoSJg98QR6rgLrN/32hZgHEATYWNo54A0rJsjNSCJQSjsTu9twfP5Oro3m4VTv4w9a6go9lcO49VW3e6SeIOfXP1kSuN0klMyUdY4PN3QKTo3hPWXgIG+bNNGVk9c= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1757408446; c=relaxed/simple; bh=ALlxNsIscQgE1MW2G44pZiPc1j/HZOfg72IZlSKTjxw=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=q2i/T/6S6H5CU/49Xy2V8y7iaw2Fx1TdP1kMWCNUPV6D80+UOrslQJ+OLX4Unj9xe3rjLUf8IJIP7TFSG8VSlDZtWQrVVlESkzVXG6fqOKLe3V+qTcsX2PC8PPArc7YyzCX19Dw8N3ekautqd5DGKzjF0UYarjegPbIE2a1NmYI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=sgONOUF3; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="sgONOUF3" Received: by smtp.kernel.org (Postfix) with ESMTPSA id A5791C4CEF4; Tue, 9 Sep 2025 09:00:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1757408445; bh=ALlxNsIscQgE1MW2G44pZiPc1j/HZOfg72IZlSKTjxw=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=sgONOUF34dJjeqWsm4AfHIk6nkiav045F+95MzjnJYOdbsmWh/JUkg+PX5R5OhQ4w Yx/fRZ+F62fNFlTq7FlRNFCS50S4LX398TReDiwU4jLbVMMJQfhZVjaFn/xFyxV+zr VTfn4orFqfWZdqxdWQy8cnOTstKKheFpSlkGww9K724pZEJfx1oLo0VRi4WfbGbm0k +4H3AcQvYjE6i/dXgYiIsugtHS/CJ4VWXW9PydWGwEPZW4ISNBJusvj4srmPppo6c9 3YkNsO3en2OoUtoMP/6Lrgi+WmYoUhD7hcxb2bUEcIn4ukqrchcxyQ8UThneoUO8AN o6jYBdNdmcr+w== Message-ID: Date: Tue, 9 Sep 2025 11:00:41 +0200 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v3 1/6] PCI: pnv_php: Properly clean up allocated IRQs on unplug To: Timothy Pearson Cc: linuxppc-dev , linux-kernel , linux-pci , Madhavan Srinivasan , Michael Ellerman , christophe leroy , Naveen N Rao , Bjorn Helgaas , Shawn Anastasio References: <1268570622.1359844.1752615109932.JavaMail.zimbra@raptorengineeringinc.com> <2013845045.1359852.1752615367790.JavaMail.zimbra@raptorengineeringinc.com> Content-Language: en-US From: Jiri Slaby Autocrypt: addr=jirislaby@kernel.org; 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charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 15. 07. 25, 23:36, Timothy Pearson wrote: > In cases where the root of a nested PCIe bridge configuration is > unplugged, the pnv_php driver would leak the allocated IRQ resources for > the child bridges' hotplug event notifications, resulting in a panic. > Fix this by walking all child buses and deallocating all it's IRQ > resources before calling pci_hp_remove_devices. > > Also modify the lifetime of the workqueue at struct pnv_php_slot::wq so > that it is only destroyed in pnv_php_free_slot, instead of > pnv_php_disable_irq. This is required since pnv_php_disable_irq will now > be called by workers triggered by hot unplug interrupts, so the > workqueue needs to stay allocated. > > The abridged kernel panic that occurs without this patch is as follows: > > WARNING: CPU: 0 PID: 687 at kernel/irq/msi.c:292 msi_device_data_release+0x6c/0x9c > CPU: 0 UID: 0 PID: 687 Comm: bash Not tainted 6.14.0-rc5+ #2 > Call Trace: > msi_device_data_release+0x34/0x9c (unreliable) > release_nodes+0x64/0x13c > devres_release_all+0xc0/0x140 > device_del+0x2d4/0x46c > pci_destroy_dev+0x5c/0x194 > pci_hp_remove_devices+0x90/0x128 > pci_hp_remove_devices+0x44/0x128 > pnv_php_disable_slot+0x54/0xd4 > power_write_file+0xf8/0x18c > pci_slot_attr_store+0x40/0x5c > sysfs_kf_write+0x64/0x78 > kernfs_fop_write_iter+0x1b0/0x290 > vfs_write+0x3bc/0x50c > ksys_write+0x84/0x140 > system_call_exception+0x124/0x230 > system_call_vectored_common+0x15c/0x2ec > > Signed-off-by: Shawn Anastasio > Signed-off-by: Timothy Pearson > --- > drivers/pci/hotplug/pnv_php.c | 94 ++++++++++++++++++++++++++++------- > 1 file changed, 75 insertions(+), 19 deletions(-) > > diff --git a/drivers/pci/hotplug/pnv_php.c b/drivers/pci/hotplug/pnv_php.c > index 573a41869c15..aec0a6d594ac 100644 > --- a/drivers/pci/hotplug/pnv_php.c > +++ b/drivers/pci/hotplug/pnv_php.c ... > @@ -647,6 +702,15 @@ static struct pnv_php_slot *pnv_php_alloc_slot(struct device_node *dn) This is preceded by: php_slot = kzalloc(sizeof(*php_slot), GFP_KERNEL); Ie. php_slot is zeroed. > return NULL; > } > > + /* Allocate workqueue for this slot's interrupt handling */ > + php_slot->wq = alloc_workqueue("pciehp-%s", 0, 0, php_slot->name); > + if (!php_slot->wq) { > + SLOT_WARN(php_slot, "Cannot alloc workqueue\n"); I believe this introduced a (unlikely) NULL ptr dereference. > + kfree(php_slot->name); > + kfree(php_slot); > + return NULL; > + } > + > if (dn->child && PCI_DN(dn->child)) > php_slot->slot_no = PCI_SLOT(PCI_DN(dn->child)->devfn); > else This continues: php_slot->pdev = bus->self; php_slot->bus = bus; And SLOT_WARN() is defined as: #define SLOT_WARN(sl, x...) \ ((sl)->pdev ? pci_warn((sl)->pdev, x) : dev_warn(&(sl)->bus->dev, x)) The else branch is alkays taken in the 'if' above, which still dereferences NULLed (sl)->bus here. > @@ -843,14 +907,6 @@ static void pnv_php_init_irq(struct pnv_php_slot *php_slot, int irq) > u16 sts, ctrl; > int ret; > > - /* Allocate workqueue */ > - php_slot->wq = alloc_workqueue("pciehp-%s", 0, 0, php_slot->name); > - if (!php_slot->wq) { > - SLOT_WARN(php_slot, "Cannot alloc workqueue\n"); Here, php_slot used to have both ->pdev and ->bus assigned at this point. > - pnv_php_disable_irq(php_slot, true); > - return; > - } > - Right? thanks, -- js suse labs