From 7c1847aa4932d988af89a12b5bc63a444ec5c5df Mon Sep 17 00:00:00 2001 From: Tetsuo Handa Date: Mon, 13 Jul 2020 11:12:54 +0900 Subject: [PATCH] driver core: Fix probe_count imbalance in really_probe() commit b292b50b0efcc7095d8bf15505fba6909bb35dce upstream. syzbot is reporting hung task in wait_for_device_probe() [1]. At least, we always need to decrement probe_count if we incremented probe_count in really_probe(). However, since I can't find "Resources present before probing" message in the console log, both "this message simply flowed off" and "syzbot is not hitting this path" will be possible. Therefore, while we are at it, let's also prepare for concurrent wait_for_device_probe() calls by replacing wake_up() with wake_up_all(). [1] https://syzkaller.appspot.com/bug?id=25c833f1983c9c1d512f4ff860dd0d7f5a2e2c0f Reported-by: syzbot Fixes: 7c35e699c88bd607 ("driver core: Print device when resources present in really_probe()") Cc: Geert Uytterhoeven Signed-off-by: Tetsuo Handa Cc: stable Link: https://lore.kernel.org/r/20200713021254.3444-1-penguin-kernel@I-love.SAKURA.ne.jp [iwamatsu: Drop patch for deferred_probe_timeout_work_func()] Signed-off-by: Nobuhiro Iwamatsu (CIP) Signed-off-by: Greg Kroah-Hartman --- drivers/base/dd.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/drivers/base/dd.c b/drivers/base/dd.c index 1d5dd37f3abe..84e757860ebb 100644 --- a/drivers/base/dd.c +++ b/drivers/base/dd.c @@ -518,7 +518,8 @@ static int really_probe(struct device *dev, struct device_driver *drv) drv->bus->name, __func__, drv->name, dev_name(dev)); if (!list_empty(&dev->devres_head)) { dev_crit(dev, "Resources present before probing\n"); - return -EBUSY; + ret = -EBUSY; + goto done; } re_probe: @@ -639,7 +640,7 @@ pinctrl_bind_failed: ret = 0; done: atomic_dec(&probe_count); - wake_up(&probe_waitqueue); + wake_up_all(&probe_waitqueue); return ret; }