driver core: Fix probe_count imbalance in really_probe()
authorTetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Mon, 13 Jul 2020 02:12:54 +0000 (11:12 +0900)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Wed, 14 Oct 2020 07:51:11 +0000 (09:51 +0200)
commit6affee7ddf0ff5d2c35f6475fc40089f3275ec59
treed88a43b6f0f61e70971859a99cf2401cc77f0d02
parente9ca1a08b162fb513c9398372a38bf37b9dc9b34
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 <syzbot+805f5f6ae37411f15b64@syzkaller.appspotmail.com>
Fixes: 7c35e699c88bd607 ("driver core: Print device when resources present in really_probe()")
Cc: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: stable <stable@kernel.org>
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) <nobuhiro1.iwamatsu@toshiba.co.jp>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
drivers/base/dd.c