When a Hyper-V framebuffer device is unbind, hyperv_fb driver tries to
release the framebuffer forcefully. If this framebuffer is in use it
produce the following WARN and hence this framebuffer is never released.
[ 44.111220] WARNING: CPU: 35 PID: 1882 at
drivers/video/fbdev/core/fb_info.c:70 framebuffer_release+0x2c/0x40
< snip >
[ 44.111289] Call Trace:
[ 44.111290] <TASK>
[ 44.111291] ? show_regs+0x6c/0x80
[ 44.111295] ? __warn+0x8d/0x150
[ 44.111298] ? framebuffer_release+0x2c/0x40
[ 44.111300] ? report_bug+0x182/0x1b0
[ 44.111303] ? handle_bug+0x6e/0xb0
[ 44.111306] ? exc_invalid_op+0x18/0x80
[ 44.111308] ? asm_exc_invalid_op+0x1b/0x20
[ 44.111311] ? framebuffer_release+0x2c/0x40
[ 44.111313] ? hvfb_remove+0x86/0xa0 [hyperv_fb]
[ 44.111315] vmbus_remove+0x24/0x40 [hv_vmbus]
[ 44.111323] device_remove+0x40/0x80
[ 44.111325] device_release_driver_internal+0x20b/0x270
[ 44.111327] ? bus_find_device+0xb3/0xf0
Fix this by moving the release of framebuffer to fb_ops.fb_destroy function
so that framebuffer framework handles it gracefully
While we fix this, also replace manual registrations/unregistration of
framebuffer with devm_register_framebuffer.
Fixes: 68a2d20b79b1 ("drivers/video: add Hyper-V Synthetic Video Frame Buffer
Driver")
Signed-off-by: Saurabh Sengar <ssen...@linux.microsoft.com>
---
drivers/video/fbdev/hyperv_fb.c | 16 ++++++++++++----
1 file changed, 12 insertions(+), 4 deletions(-)
diff --git a/drivers/video/fbdev/hyperv_fb.c b/drivers/video/fbdev/hyperv_fb.c
index 363e4ccfcdb7..83b1ab4da984 100644
--- a/drivers/video/fbdev/hyperv_fb.c
+++ b/drivers/video/fbdev/hyperv_fb.c
@@ -862,6 +862,16 @@ static void hvfb_ops_damage_area(struct fb_info *info, u32
x, u32 y, u32 width,
hvfb_ondemand_refresh_throttle(par, x, y, width, height);
}
+/*
+ * fb_ops.fb_destroy is called by the last put_fb_info() call at the end
+ * of unregister_framebuffer() or fb_release(). Do any cleanup related to
+ * framebuffer here.
+ */
+static void hvfb_destroy(struct fb_info *info)
+{
+ framebuffer_release(info);
+}
+
/*
* TODO: GEN1 codepaths allocate from system or DMA-able memory. Fix the
* driver to use the _SYSMEM_ or _DMAMEM_ helpers in these cases.
@@ -877,6 +887,7 @@ static const struct fb_ops hvfb_ops = {
.fb_set_par = hvfb_set_par,
.fb_setcolreg = hvfb_setcolreg,
.fb_blank = hvfb_blank,
+ .fb_destroy = hvfb_destroy,
};
/* Get options from kernel paramenter "video=" */
@@ -1172,7 +1183,7 @@ static int hvfb_probe(struct hv_device *hdev,
if (ret)
goto error;
- ret = register_framebuffer(info);
+ ret = devm_register_framebuffer(&hdev->device, info);
if (ret) {
pr_err("Unable to register framebuffer\n");
goto error;
@@ -1220,14 +1231,11 @@ static void hvfb_remove(struct hv_device *hdev)
fb_deferred_io_cleanup(info);
- unregister_framebuffer(info);
cancel_delayed_work_sync(&par->dwork);
vmbus_close(hdev->channel);
- hv_set_drvdata(hdev, NULL);
hvfb_putmem(hdev, info);
- framebuffer_release(info);
}
static int hvfb_suspend(struct hv_device *hdev)
--
2.43.0
