[lkml]   [2019]   [Mar]   [29]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
Patch in this message
Subject[PATCH AUTOSEL 4.19 40/57] kvm: properly check debugfs dentry before using it
From: Greg Kroah-Hartman <>

[ Upstream commit 8ed0579c12b2fe56a1fac2f712f58fc26c1dc49b ]

debugfs can now report an error code if something went wrong instead of
just NULL. So if the return value is to be used as a "real" dentry, it
needs to be checked if it is an error before dereferencing it.

This is now happening because of ff9fb72bc077 ("debugfs: return error
values, not NULL"). syzbot has found a way to trigger multiple debugfs
files attempting to be created, which fails, and then the error code
gets passed to dentry_path_raw() which obviously does not like it.

Reported-by: Eric Biggers <>
Cc: "Radim Krčmář" <>
Acked-by: Paolo Bonzini <>
Signed-off-by: Greg Kroah-Hartman <>
Signed-off-by: Linus Torvalds <>
Signed-off-by: Sasha Levin <>
virt/kvm/kvm_main.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index c436d95fd7aa..fb74f994cb63 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -3912,7 +3912,7 @@ static void kvm_uevent_notify_change(unsigned int type, struct kvm *kvm)
add_uevent_var(env, "PID=%d", kvm->userspace_pid);

- if (kvm->debugfs_dentry) {
+ if (!IS_ERR_OR_NULL(kvm->debugfs_dentry)) {
char *tmp, *p = kmalloc(PATH_MAX, GFP_KERNEL);

if (p) {
 \ /
  Last update: 2019-03-30 02:39    [W:0.182 / U:3.724 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site