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Filename Latest commit message Latest commit date
Josef Bacik 6cd3f13aaa nfs: fix UAF in direct writes
commit 17f46b803d4f23c66cacce81db35fef3adb8f2af upstream.

In production we have been hitting the following warning consistently

------------[ cut here ]------------
refcount_t: underflow; use-after-free.
WARNING: CPU: 17 PID: 1800359 at lib/refcount.c:28 refcount_warn_saturate+0x9c/0xe0
Workqueue: nfsiod nfs_direct_write_schedule_work [nfs]
RIP: 0010:refcount_warn_saturate+0x9c/0xe0
PKRU: 55555554
Call Trace:
 <TASK>
 ? __warn+0x9f/0x130
 ? refcount_warn_saturate+0x9c/0xe0
 ? report_bug+0xcc/0x150
 ? handle_bug+0x3d/0x70
 ? exc_invalid_op+0x16/0x40
 ? asm_exc_invalid_op+0x16/0x20
 ? refcount_warn_saturate+0x9c/0xe0
 nfs_direct_write_schedule_work+0x237/0x250 [nfs]
 process_one_work+0x12f/0x4a0
 worker_thread+0x14e/0x3b0
 ? ZSTD_getCParams_internal+0x220/0x220
 kthread+0xdc/0x120
 ? __btf_name_valid+0xa0/0xa0
 ret_from_fork+0x1f/0x30

This is because we're completing the nfs_direct_request twice in a row.

The source of this is when we have our commit requests to submit, we
process them and send them off, and then in the completion path for the
commit requests we have

if (nfs_commit_end(cinfo.mds))
	nfs_direct_write_complete(dreq);

However since we're submitting asynchronous requests we sometimes have
one that completes before we submit the next one, so we end up calling
complete on the nfs_direct_request twice.

The only other place we use nfs_generic_commit_list() is in
__nfs_commit_inode, which wraps this call in a

nfs_commit_begin();
nfs_commit_end();

Which is a common pattern for this style of completion handling, one
that is also repeated in the direct code with get_dreq()/put_dreq()
calls around where we process events as well as in the completion paths.

Fix this by using the same pattern for the commit requests.

Before with my 200 node rocksdb stress running this warning would pop
every 10ish minutes.  With my patch the stress test has been running for
several hours without popping.

Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Cc: stable@vger.kernel.org
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
[ chanho : Backports v5.4.y, commit 133a48abf6ec (NFS: Fix up commit deadlocks)
  is needed to use nfs_commit_end ]
Signed-off-by: Chanho Min <chanho.min@lge.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-08-28 16:21:37 +02:00
arch x86/fpu: Delay instruction pointer fixup until after warning 2025-08-28 16:21:34 +02:00
block
certs
crypto crypto: algif_hash - fix double free in hash_accept 2025-06-04 14:32:35 +02:00
Documentation Documentation: ACPI: Fix parent device references 2025-08-28 16:21:23 +02:00
drivers media: venus: hfi: explicitly release IRQ during teardown 2025-08-28 16:21:35 +02:00
fs nfs: fix UAF in direct writes 2025-08-28 16:21:37 +02:00
include nfs: fix UAF in direct writes 2025-08-28 16:21:37 +02:00
init bpfilter: match bit size of bpfilter_umh to that of the kernel 2025-07-17 18:24:51 +02:00
ipc ipc: fix to protect IPCS lookups using RCU 2025-06-27 11:02:52 +01:00
kernel mm: drop the assumption that VM_SHARED always implies writable 2025-08-28 16:21:36 +02:00
lib lib: test_objagg: Set error message in check_expect_hints_stats() 2025-07-17 18:24:56 +02:00
LICENSES
mm mm: perform the mapping_map_writable() check after call_mmap() 2025-08-28 16:21:36 +02:00
net Bluetooth: fix use-after-free in device_for_each_child() 2025-08-28 16:21:36 +02:00
samples samples: mei: Fix building on musl libc 2025-08-28 16:21:19 +02:00
scripts kbuild: Add KBUILD_CPPFLAGS to as-option invocation 2025-08-28 16:21:33 +02:00
security securityfs: don't pin dentries twice, once is enough... 2025-08-28 16:21:24 +02:00
sound ALSA: scarlett2: Add retry on -EPROTO from scarlett2_usb_tx() 2025-08-28 16:21:34 +02:00
tools act_mirred: use the backlog for nested calls to mirred ingress 2025-08-28 16:21:36 +02:00
usr kbuild: hdrcheck: fix cross build with clang 2025-07-17 18:24:51 +02:00
virt
.clang-format
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore
.mailmap
COPYING
CREDITS
Kbuild
Kconfig
MAINTAINERS platform: Add Surface platform directory 2025-06-27 11:02:56 +01:00
Makefile kbuild: add $(CLANG_FLAGS) to KBUILD_CPPFLAGS 2025-08-28 16:21:33 +02:00
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