| Date | Wed, 09 Nov 2011 13:27:17 -0800 | From | Greg KH <> | Subject | [115/262] fb: sh-mobile: Fix deadlock risk between lock_fb_info() and console_lock() |
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3.0-stable review patch. If anyone has any objections, please let me know.
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From: =?UTF-8?q?Bruno=20Pr=C3=A9mont?= <bonbons@linux-vserver.org>
commit 4a47a0e09c504e3ce0ccdb405411aefc5b09deb8 upstream.
Following on Herton's patch "fb: avoid possible deadlock caused by fb_set_suspend" which moves lock_fb_info() out of fb_set_suspend() to its callers, correct sh-mobile's locking around call to fb_set_suspend() and the same sort of deaklocks with console_lock() due to order of taking the lock.
console_lock() must be taken while fb_info is already locked and fb_info must be locked while calling fb_set_suspend().
Signed-off-by: Bruno Prémont <bonbons@linux-vserver.org> Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de> Signed-off-by: Florian Tobias Schandinat <FlorianSchandinat@gmx.de> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
--- drivers/video/sh_mobile_hdmi.c | 47 ++++++++++++++++++++++------------------- 1 file changed, 26 insertions(+), 21 deletions(-)
--- a/drivers/video/sh_mobile_hdmi.c +++ b/drivers/video/sh_mobile_hdmi.c @@ -1111,6 +1111,7 @@ static long sh_hdmi_clk_configure(struct static void sh_hdmi_edid_work_fn(struct work_struct *work) { struct sh_hdmi *hdmi = container_of(work, struct sh_hdmi, edid_work.work); + struct fb_info *info; struct sh_mobile_hdmi_info *pdata = hdmi->dev->platform_data; struct sh_mobile_lcdc_chan *ch; int ret; @@ -1123,8 +1124,9 @@ static void sh_hdmi_edid_work_fn(struct mutex_lock(&hdmi->mutex); + info = hdmi->info; + if (hdmi->hp_state == HDMI_HOTPLUG_CONNECTED) { - struct fb_info *info = hdmi->info; unsigned long parent_rate = 0, hdmi_rate; ret = sh_hdmi_read_edid(hdmi, &hdmi_rate, &parent_rate); @@ -1148,42 +1150,45 @@ static void sh_hdmi_edid_work_fn(struct ch = info->par; - console_lock(); + if (lock_fb_info(info)) { + console_lock(); - /* HDMI plug in */ - if (!sh_hdmi_must_reconfigure(hdmi) && - info->state == FBINFO_STATE_RUNNING) { - /* - * First activation with the default monitor - just turn - * on, if we run a resume here, the logo disappears - */ - if (lock_fb_info(info)) { + /* HDMI plug in */ + if (!sh_hdmi_must_reconfigure(hdmi) && + info->state == FBINFO_STATE_RUNNING) { + /* + * First activation with the default monitor - just turn + * on, if we run a resume here, the logo disappears + */ info->var.width = hdmi->var.width; info->var.height = hdmi->var.height; sh_hdmi_display_on(hdmi, info); - unlock_fb_info(info); + } else { + /* New monitor or have to wake up */ + fb_set_suspend(info, 0); } - } else { - /* New monitor or have to wake up */ - fb_set_suspend(info, 0); - } - console_unlock(); + console_unlock(); + unlock_fb_info(info); + } } else { ret = 0; - if (!hdmi->info) + if (!info) goto out; hdmi->monspec.modedb_len = 0; fb_destroy_modedb(hdmi->monspec.modedb); hdmi->monspec.modedb = NULL; - console_lock(); + if (lock_fb_info(info)) { + console_lock(); - /* HDMI disconnect */ - fb_set_suspend(hdmi->info, 1); + /* HDMI disconnect */ + fb_set_suspend(info, 1); - console_unlock(); + console_unlock(); + unlock_fb_info(info); + } } out:
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