lkml.org 
[lkml]   [2024]   [Mar]   [13]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH 1/2] xen/evtchn: avoid WARN() when unbinding an event channel
Date
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 <demi@invisiblethingslab.com>
Tested-by: Demi Marie Obenour <demi@invisiblethingslab.com>
Signed-off-by: Juergen Gross <jgross@suse.com>
---
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;
};

static void evtchn_free_ring(evtchn_port_t *ring)
@@ -164,6 +165,10 @@ static irqreturn_t evtchn_interrupt(int irq, void *data)
struct per_user_data *u = evtchn->user;
unsigned int prod, cons;

+ /* 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_data *u,

BUG_ON(irq < 0);

+ evtchn->unbinding = true;
unbind_from_irqhandler(irq, evtchn);

del_evtchn(u, evtchn);
--
2.35.3

\
 
 \ /
  Last update: 2024-03-13 08:14    [W:0.078 / U:0.076 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site