From mboxrd@z Thu Jan 1 00:00:00 1970 From: ravi.bangoria@linux.ibm.com (Ravi Bangoria) Date: Wed, 14 Nov 2018 13:49:21 +0530 Subject: [PATCH] Uprobes: Fix kernel oops with delayed_uprobe_remove() Message-ID: <20181114081921.26484-1-ravi.bangoria@linux.ibm.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org syzbot reported a kernel crash with delayed_uprobe_remove(): https://lkml.org/lkml/2018/11/1/1244 Backtrace mentioned in the link points to a race between process exit and uprobe_unregister(). Fix it by locking delayed_uprobe_lock before calling delayed_uprobe_remove() from put_uprobe(). Reported-by: syzbot+cb1fb754b771caca0a88 at syzkaller.appspotmail.com Signed-off-by: Ravi Bangoria --- kernel/events/uprobes.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c index 96fb51f3994f..e527c4753d4f 100644 --- a/kernel/events/uprobes.c +++ b/kernel/events/uprobes.c @@ -572,7 +572,9 @@ static void put_uprobe(struct uprobe *uprobe) * gets called, we don't get a chance to remove uprobe from * delayed_uprobe_list from remove_breakpoint(). Do it here. */ + mutex_lock(&delayed_uprobe_lock); delayed_uprobe_remove(uprobe, NULL); + mutex_unlock(&delayed_uprobe_lock); kfree(uprobe); } } -- 2.19.1