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Wed, 13 Mar 2024 07:14:18 +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 i4BMGEpS8WWtSAAAD6G6ig (envelope-from ); Wed, 13 Mar 2024 07:14:18 +0000 From: Juergen Gross To: linux-kernel@vger.kernel.org Cc: Juergen Gross , Stefano Stabellini , Oleksandr Tyshchenko , xen-devel@lists.xenproject.org, Demi Marie Obenour Subject: [PATCH 1/2] xen/evtchn: avoid WARN() when unbinding an event channel Date: Wed, 13 Mar 2024 08:14:08 +0100 Message-Id: <20240313071409.25913-2-jgross@suse.com> X-Mailer: git-send-email 2.35.3 In-Reply-To: <20240313071409.25913-1-jgross@suse.com> References: <20240313071409.25913-1-jgross@suse.com> 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 X-Spamd-Bar: ++++ Authentication-Results: smtp-out2.suse.de; dkim=pass header.d=suse.com header.s=susede1 header.b=rdFQ6nU0 X-Spamd-Result: default: False [4.69 / 50.00]; RCVD_VIA_SMTP_AUTH(0.00)[]; TO_DN_SOME(0.00)[]; R_MISSING_CHARSET(2.50)[]; BROKEN_CONTENT_TYPE(1.50)[]; RCPT_COUNT_FIVE(0.00)[6]; RCVD_COUNT_THREE(0.00)[3]; DKIM_TRACE(0.00)[suse.com:+]; MX_GOOD(-0.01)[]; FROM_EQ_ENVFROM(0.00)[]; MIME_TRACE(0.00)[0:+]; BAYES_HAM(-0.00)[27.98%]; ARC_NA(0.00)[]; R_DKIM_ALLOW(-0.20)[suse.com:s=susede1]; FROM_HAS_DN(0.00)[]; TO_MATCH_ENVRCPT_ALL(0.00)[]; MIME_GOOD(-0.10)[text/plain]; DKIM_SIGNED(0.00)[suse.com:s=susede1]; MID_CONTAINS_FROM(1.00)[]; DBL_BLOCKED_OPENRESOLVER(0.00)[suse.com:email,suse.com:dkim]; FUZZY_BLOCKED(0.00)[rspamd.com]; RCVD_TLS_ALL(0.00)[]; RBL_SPAMHAUS_BLOCKED_OPENRESOLVER(0.00)[2a07:de40:b281:104:10:150:64:97:from] X-Spam-Score: 4.69 X-Spam-Level: **** X-Rspamd-Queue-Id: A14D61F7A4 X-Spam-Flag: NO X-Rspamd-Server: rspamd1.dmz-prg2.suse.org Content-Type: text/plain; charset="utf-8" When unbinding a user event channel, the related handler might be called a last time in case the kernel was built with CONFIG_DEBUG_SHIRQ. This might cause a WARN() in the handler. Avoid that by adding an "unbinding" flag to struct user_event which will short circuit the handler. Fixes: 9e90e58c11b7 ("xen: evtchn: Allow shared registration of IRQ handers= ") Reported-by: Demi Marie Obenour Tested-by: Demi Marie Obenour Signed-off-by: Juergen Gross Reviewed-by: Oleksandr Tyshchenko --- drivers/xen/evtchn.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/drivers/xen/evtchn.c b/drivers/xen/evtchn.c index 59717628ca42..f6a2216c2c87 100644 --- a/drivers/xen/evtchn.c +++ b/drivers/xen/evtchn.c @@ -85,6 +85,7 @@ struct user_evtchn { struct per_user_data *user; evtchn_port_t port; bool enabled; + bool unbinding; }; =20 static void evtchn_free_ring(evtchn_port_t *ring) @@ -164,6 +165,10 @@ static irqreturn_t evtchn_interrupt(int irq, void *dat= a) struct per_user_data *u =3D evtchn->user; unsigned int prod, cons; =20 + /* Handler might be called when tearing down the IRQ. */ + if (evtchn->unbinding) + return IRQ_HANDLED; + WARN(!evtchn->enabled, "Interrupt for port %u, but apparently not enabled; per-user %p\n", evtchn->port, u); @@ -421,6 +426,7 @@ static void evtchn_unbind_from_user(struct per_user_dat= a *u, =20 BUG_ON(irq < 0); =20 + evtchn->unbinding =3D true; unbind_from_irqhandler(irq, evtchn); =20 del_evtchn(u, evtchn); --=20 2.35.3 From nobody Wed May 22 03:23:40 2024 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 218DE225DE for ; Wed, 13 Mar 2024 07:14:25 +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=1710314067; cv=none; b=rSKEsTxZUqh944KG/Jhl5NTO0kxo7q/uVR9XMgYYoV64fQEpVsPPrZkXa0kYtQUn2PnKvGJeywWKSbuJ1UXQzhrLuI/zxZZhbDYon6kKWMFYWfmwUHQQwF03z8sln6MwUepa2T5qg17iQBEUA8RfiAQsuW/0pBxy5EVA9ZKsuAw= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1710314067; c=relaxed/simple; bh=U0jSC2h7kQCcpgHrk1T0gyWetAKWJfKBKkwLYdLb4x4=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; 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Wed, 13 Mar 2024 07:14:24 +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 dM3kAlBS8WWySAAAD6G6ig (envelope-from ); Wed, 13 Mar 2024 07:14:24 +0000 From: Juergen Gross To: linux-kernel@vger.kernel.org Cc: Juergen Gross , Stefano Stabellini , Oleksandr Tyshchenko , xen-devel@lists.xenproject.org Subject: [PATCH 2/2] xen/events: increment refcnt only if event channel is refcounted Date: Wed, 13 Mar 2024 08:14:09 +0100 Message-Id: <20240313071409.25913-3-jgross@suse.com> X-Mailer: git-send-email 2.35.3 In-Reply-To: <20240313071409.25913-1-jgross@suse.com> References: <20240313071409.25913-1-jgross@suse.com> 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 X-Spam-Level: *** X-Spamd-Bar: +++ Authentication-Results: smtp-out2.suse.de; dkim=pass header.d=suse.com header.s=susede1 header.b=UoywMclp X-Rspamd-Server: rspamd2.dmz-prg2.suse.org X-Spamd-Result: default: False [3.49 / 50.00]; ARC_NA(0.00)[]; RCVD_VIA_SMTP_AUTH(0.00)[]; R_DKIM_ALLOW(-0.20)[suse.com:s=susede1]; SPAMHAUS_XBL(0.00)[2a07:de40:b281:104:10:150:64:97:from]; FROM_HAS_DN(0.00)[]; TO_DN_SOME(0.00)[]; R_MISSING_CHARSET(2.50)[]; TO_MATCH_ENVRCPT_ALL(0.00)[]; MIME_GOOD(-0.10)[text/plain]; BROKEN_CONTENT_TYPE(1.50)[]; RCPT_COUNT_FIVE(0.00)[5]; NEURAL_HAM_LONG(-1.00)[-1.000]; RCVD_COUNT_THREE(0.00)[3]; DKIM_SIGNED(0.00)[suse.com:s=susede1]; DKIM_TRACE(0.00)[suse.com:+]; MX_GOOD(-0.01)[]; MID_CONTAINS_FROM(1.00)[]; DBL_BLOCKED_OPENRESOLVER(0.00)[suse.com:dkim,suse.com:email]; FUZZY_BLOCKED(0.00)[rspamd.com]; FROM_EQ_ENVFROM(0.00)[]; MIME_TRACE(0.00)[0:+]; NEURAL_HAM_SHORT(-0.20)[-0.995]; RCVD_TLS_ALL(0.00)[] X-Spam-Score: 3.49 X-Rspamd-Queue-Id: 4C52E1F7A4 X-Spam-Flag: NO Content-Type: text/plain; charset="utf-8" In bind_evtchn_to_irq_chip() don't increment the refcnt of the event channel blindly. In case the event channel is NOT refcounted, issue a warning instead. Add an additional safety net by doing the refcnt increment only if the caller has specified IRQF_SHARED in the irqflags parameter. Fixes: 9e90e58c11b7 ("xen: evtchn: Allow shared registration of IRQ handers= ") Signed-off-by: Juergen Gross Reviewed-by: Oleksandr Tyshchenko --- drivers/xen/events/events_base.c | 22 +++++++++++++--------- 1 file changed, 13 insertions(+), 9 deletions(-) diff --git a/drivers/xen/events/events_base.c b/drivers/xen/events/events_b= ase.c index 2faa4bf78c7a..81effbd53dc5 100644 --- a/drivers/xen/events/events_base.c +++ b/drivers/xen/events/events_base.c @@ -1190,7 +1190,7 @@ int xen_pirq_from_irq(unsigned irq) EXPORT_SYMBOL_GPL(xen_pirq_from_irq); =20 static int bind_evtchn_to_irq_chip(evtchn_port_t evtchn, struct irq_chip *= chip, - struct xenbus_device *dev) + struct xenbus_device *dev, bool shared) { int ret =3D -ENOMEM; struct irq_info *info; @@ -1224,7 +1224,8 @@ static int bind_evtchn_to_irq_chip(evtchn_port_t evtc= hn, struct irq_chip *chip, */ bind_evtchn_to_cpu(info, 0, false); } else if (!WARN_ON(info->type !=3D IRQT_EVTCHN)) { - info->refcnt++; + if (shared && !WARN_ON(info->refcnt < 0)) + info->refcnt++; } =20 ret =3D info->irq; @@ -1237,13 +1238,13 @@ static int bind_evtchn_to_irq_chip(evtchn_port_t ev= tchn, struct irq_chip *chip, =20 int bind_evtchn_to_irq(evtchn_port_t evtchn) { - return bind_evtchn_to_irq_chip(evtchn, &xen_dynamic_chip, NULL); + return bind_evtchn_to_irq_chip(evtchn, &xen_dynamic_chip, NULL, false); } EXPORT_SYMBOL_GPL(bind_evtchn_to_irq); =20 int bind_evtchn_to_irq_lateeoi(evtchn_port_t evtchn) { - return bind_evtchn_to_irq_chip(evtchn, &xen_lateeoi_chip, NULL); + return bind_evtchn_to_irq_chip(evtchn, &xen_lateeoi_chip, NULL, false); } EXPORT_SYMBOL_GPL(bind_evtchn_to_irq_lateeoi); =20 @@ -1295,7 +1296,8 @@ static int bind_ipi_to_irq(unsigned int ipi, unsigned= int cpu) =20 static int bind_interdomain_evtchn_to_irq_chip(struct xenbus_device *dev, evtchn_port_t remote_port, - struct irq_chip *chip) + struct irq_chip *chip, + bool shared) { struct evtchn_bind_interdomain bind_interdomain; int err; @@ -1307,14 +1309,14 @@ static int bind_interdomain_evtchn_to_irq_chip(stru= ct xenbus_device *dev, &bind_interdomain); =20 return err ? : bind_evtchn_to_irq_chip(bind_interdomain.local_port, - chip, dev); + chip, dev, shared); } =20 int bind_interdomain_evtchn_to_irq_lateeoi(struct xenbus_device *dev, evtchn_port_t remote_port) { return bind_interdomain_evtchn_to_irq_chip(dev, remote_port, - &xen_lateeoi_chip); + &xen_lateeoi_chip, false); } EXPORT_SYMBOL_GPL(bind_interdomain_evtchn_to_irq_lateeoi); =20 @@ -1430,7 +1432,8 @@ static int bind_evtchn_to_irqhandler_chip(evtchn_port= _t evtchn, { int irq, retval; =20 - irq =3D bind_evtchn_to_irq_chip(evtchn, chip, NULL); + irq =3D bind_evtchn_to_irq_chip(evtchn, chip, NULL, + irqflags & IRQF_SHARED); if (irq < 0) return irq; retval =3D request_irq(irq, handler, irqflags, devname, dev_id); @@ -1471,7 +1474,8 @@ static int bind_interdomain_evtchn_to_irqhandler_chip( { int irq, retval; =20 - irq =3D bind_interdomain_evtchn_to_irq_chip(dev, remote_port, chip); + irq =3D bind_interdomain_evtchn_to_irq_chip(dev, remote_port, chip, + irqflags & IRQF_SHARED); if (irq < 0) return irq; =20 --=20 2.35.3