Fix several issues with reference counting in
rootdir_make_translated_node ():
* Grab an additional reference while still holding the lock.
* Give the node an additional reference for being pointed to
by the ops.
* Reference the existing node if we find it on the second try,
not only if we find it on the first try.
* Dereference, not just clean, the created node if it turns out
to be unneeded.
Fixes a crash with the following backtrace:
#2 0x010855c8 in __assert_fail_backtrace (
assertion=0x1051148 "! (r.hard == 1 && r.weak == 0) || !\"refcount
detected use-after-free!\"",
file=0x1050cec "../../libshouldbeinlibc/refcount.h", line=170,
function=0x1051220 <__PRETTY_FUNCTION__.3> "refcounts_ref")
at ../../libshouldbeinlibc/assert-backtrace.c:64
#3 0x01050358 in refcounts_ref (result=0x0, ref=0x15009a0) at
../../libshouldbeinlibc/refcount.h:170
#4 netfs_nref (np=0x15008f0) at ../../libnetfs/nref.c:26
#5 0x0804c9f4 in rootdir_make_translated_node (dir_hook=0x10001990,
entry_hook=0x8055180 <__compound_literal.8>)
at ../../procfs/rootdir.c:674
#6 0x0804ace3 in procfs_dir_lookup (hook=0x10001c10, name=0x2857efc "mounts",
np=0x2855d68) at ../../procfs/procfs_dir.c:88
#7 0x0804a410 in procfs_lookup (np=0x10001c40, name=0x2857efc "mounts",
npp=0x2855d68) at ../../procfs/procfs.c:185
#8 0x0804cae5 in dircat_lookup (hook=0x10001d50, name=0x2857efc "mounts",
np=0x2855d68) at ../../procfs/dircat.c:76
#9 0x0804a410 in procfs_lookup (np=0x10001d80, name=0x2857efc "mounts",
npp=0x2855d68) at ../../procfs/procfs.c:185
#10 0x0804a96f in netfs_attempt_lookup (user=0x1401c60, dir=0x10001d80,
name=0x2857efc "mounts", np=0x2855d68)
at ../../procfs/netfs.c:212
#11 0x0103fd5b in netfs_S_dir_lookup (dircred=<optimized out>,
filename=<optimized out>, flags=<optimized out>,
mode=<optimized out>, do_retry=<optimized out>, retry_name=<optimized
out>, retry_port=<optimized out>,
retry_port_type=<optimized out>) at ../../libnetfs/dir-lookup.c:175
---
procfs/rootdir.c | 10 +++++-----
1 file changed, 5 insertions(+), 5 deletions(-)
diff --git a/procfs/rootdir.c b/procfs/rootdir.c
index 9f860a91..0e7c05c0 100644
--- a/procfs/rootdir.c
+++ b/procfs/rootdir.c
@@ -667,13 +667,12 @@ rootdir_make_translated_node (void *dir_hook, const void
*entry_hook)
pthread_spin_lock (&rootdir_translated_node_lock);
np = *ops->npp;
+ if (np != NULL)
+ netfs_nref (np);
pthread_spin_unlock (&rootdir_translated_node_lock);
if (np != NULL)
- {
- netfs_nref (np);
- return np;
- }
+ return np;
np = procfs_make_node (entry_hook, (void *) entry_hook);
if (np == NULL)
@@ -686,11 +685,12 @@ rootdir_make_translated_node (void *dir_hook, const void
*entry_hook)
prev = *ops->npp;
if (*ops->npp == NULL)
*ops->npp = np;
+ netfs_nref (*ops->npp);
pthread_spin_unlock (&rootdir_translated_node_lock);
if (prev != NULL)
{
- procfs_cleanup (np);
+ netfs_nrele (np);
np = prev;
}
--
2.31.1
