Here are two fixes related to MPTCP.
The first patch fixes when the MPTcpExtMPCapableFallbackACK MIB counter
is modified: it should only be incremented when a connection was using
MPTCP options, but then a fallback to TCP has been done. This patch also
checks the counter is not incremented by mistake during the connect
selftests. This counter was wrongly incremented since its introduction
in v5.7.
The second patch fixes a wrong parsing of the 'dev' endpoint options in
the selftests: the wrong variable was used. This option was not used
before, but it is going to be soon. This issue is visible since v5.18.
Signed-off-by: Matthieu Baerts (NGI0) <matttbe(a)kernel.org>
---
Davide Caratti (1):
mptcp: don't account accept() of non-MPC client as fallback to TCP
Geliang Tang (1):
selftests: mptcp: join: fix dev in check_endpoint
net/mptcp/protocol.c | 2 --
net/mptcp/subflow.c | 2 ++
tools/testing/selftests/net/mptcp/mptcp_connect.sh | 9 +++++++++
tools/testing/selftests/net/mptcp/mptcp_join.sh | 4 +++-
4 files changed, 14 insertions(+), 3 deletions(-)
---
base-commit: 0ba80d96585662299d4ea4624043759ce9015421
change-id: 20240329-upstream-net-20240329-fallback-mib-b0fec9c6189b
Best regards,
--
Matthieu Baerts (NGI0) <matttbe(a)kernel.org>
After an innocuous optimization change in LLVM main (19.0.0), x86_64
allmodconfig (which enables CONFIG_KCSAN / -fsanitize=thread) fails to
build due to the checks in check_copy_size():
In file included from net/bluetooth/sco.c:27:
In file included from include/linux/module.h:13:
In file included from include/linux/stat.h:19:
In file included from include/linux/time.h:60:
In file included from include/linux/time32.h:13:
In file included from include/linux/timex.h:67:
In file included from arch/x86/include/asm/timex.h:6:
In file included from arch/x86/include/asm/tsc.h:10:
In file included from arch/x86/include/asm/msr.h:15:
In file included from include/linux/percpu.h:7:
In file included from include/linux/smp.h:118:
include/linux/thread_info.h:244:4: error: call to '__bad_copy_from' declared with 'error' attribute: copy source size is too small
244 | __bad_copy_from();
| ^
The same exact error occurs in l2cap_sock.c. The copy_to_user()
statements that are failing come from l2cap_sock_getsockopt_old() and
sco_sock_getsockopt_old(). This does not occur with GCC with or without
KCSAN or Clang without KCSAN enabled.
len is defined as an 'int' because it is assigned from
'__user int *optlen'. However, it is clamped against the result of
sizeof(), which has a type of 'size_t' ('unsigned long' for 64-bit
platforms). This is done with min_t() because min() requires compatible
types, which results in both len and the result of sizeof() being casted
to 'unsigned int', meaning len changes signs and the result of sizeof()
is truncated. From there, len is passed to copy_to_user(), which has a
third parameter type of 'unsigned long', so it is widened and changes
signs again. This excessive casting in combination with the KCSAN
instrumentation causes LLVM to fail to eliminate the __bad_copy_from()
call, failing the build.
The official recommendation from LLVM developers is to consistently use
long types for all size variables to avoid the unnecessary casting in
the first place. Change the type of len to size_t in both
l2cap_sock_getsockopt_old() and sco_sock_getsockopt_old(). This clears
up the error while allowing min_t() to be replaced with min(), resulting
in simpler code with no casts and fewer implicit conversions. While len
is a different type than optlen now, it should result in no functional
change because the result of sizeof() will clamp all values of optlen in
the same manner as before.
Cc: stable(a)vger.kernel.org
Closes: https://github.com/ClangBuiltLinux/linux/issues/2007
Link: https://github.com/llvm/llvm-project/issues/85647
Signed-off-by: Nathan Chancellor <nathan(a)kernel.org>
---
net/bluetooth/l2cap_sock.c | 7 ++++---
net/bluetooth/sco.c | 7 ++++---
2 files changed, 8 insertions(+), 6 deletions(-)
diff --git a/net/bluetooth/l2cap_sock.c b/net/bluetooth/l2cap_sock.c
index 4287aa6cc988..81193427bf05 100644
--- a/net/bluetooth/l2cap_sock.c
+++ b/net/bluetooth/l2cap_sock.c
@@ -439,7 +439,8 @@ static int l2cap_sock_getsockopt_old(struct socket *sock, int optname,
struct l2cap_chan *chan = l2cap_pi(sk)->chan;
struct l2cap_options opts;
struct l2cap_conninfo cinfo;
- int len, err = 0;
+ int err = 0;
+ size_t len;
u32 opt;
BT_DBG("sk %p", sk);
@@ -486,7 +487,7 @@ static int l2cap_sock_getsockopt_old(struct socket *sock, int optname,
BT_DBG("mode 0x%2.2x", chan->mode);
- len = min_t(unsigned int, len, sizeof(opts));
+ len = min(len, sizeof(opts));
if (copy_to_user(optval, (char *) &opts, len))
err = -EFAULT;
@@ -536,7 +537,7 @@ static int l2cap_sock_getsockopt_old(struct socket *sock, int optname,
cinfo.hci_handle = chan->conn->hcon->handle;
memcpy(cinfo.dev_class, chan->conn->hcon->dev_class, 3);
- len = min_t(unsigned int, len, sizeof(cinfo));
+ len = min(len, sizeof(cinfo));
if (copy_to_user(optval, (char *) &cinfo, len))
err = -EFAULT;
diff --git a/net/bluetooth/sco.c b/net/bluetooth/sco.c
index 43daf965a01e..9a72d7f1946c 100644
--- a/net/bluetooth/sco.c
+++ b/net/bluetooth/sco.c
@@ -967,7 +967,8 @@ static int sco_sock_getsockopt_old(struct socket *sock, int optname,
struct sock *sk = sock->sk;
struct sco_options opts;
struct sco_conninfo cinfo;
- int len, err = 0;
+ int err = 0;
+ size_t len;
BT_DBG("sk %p", sk);
@@ -989,7 +990,7 @@ static int sco_sock_getsockopt_old(struct socket *sock, int optname,
BT_DBG("mtu %u", opts.mtu);
- len = min_t(unsigned int, len, sizeof(opts));
+ len = min(len, sizeof(opts));
if (copy_to_user(optval, (char *)&opts, len))
err = -EFAULT;
@@ -1007,7 +1008,7 @@ static int sco_sock_getsockopt_old(struct socket *sock, int optname,
cinfo.hci_handle = sco_pi(sk)->conn->hcon->handle;
memcpy(cinfo.dev_class, sco_pi(sk)->conn->hcon->dev_class, 3);
- len = min_t(unsigned int, len, sizeof(cinfo));
+ len = min(len, sizeof(cinfo));
if (copy_to_user(optval, (char *)&cinfo, len))
err = -EFAULT;
---
base-commit: 7835fcfd132eb88b87e8eb901f88436f63ab60f7
change-id: 20240401-bluetooth-fix-len-type-getsockopt_old-73c4a8e60444
Best regards,
--
Nathan Chancellor <nathan(a)kernel.org>
The `module!` macro creates glue code that are called by C to initialize
the Rust modules using the `Module::init` function. Part of this glue
code are the local functions `__init` and `__exit` that are used to
initialize/destroy the Rust module.
These functions are safe and also visible to the Rust mod in which the
`module!` macro is invoked. This means that they can be called by other
safe Rust code. But since they contain `unsafe` blocks that rely on only
being called at the right time, this is a soundness issue.
Wrap these generated functions inside of two private modules, this
guarantees that the public functions cannot be called from the outside.
Make the safe functions `unsafe` and add SAFETY comments.
Cc: stable(a)vger.kernel.org
Closes: https://github.com/Rust-for-Linux/linux/issues/629
Fixes: 1fbde52bde73 ("rust: add `macros` crate")
Signed-off-by: Benno Lossin <benno.lossin(a)proton.me>
---
This patch is best viewed with `git show --ignore-space-change`, since I
also adjusted the indentation.
rust/macros/module.rs | 198 ++++++++++++++++++++++++------------------
1 file changed, 112 insertions(+), 86 deletions(-)
diff --git a/rust/macros/module.rs b/rust/macros/module.rs
index 27979e582e4b..16c4921a08f2 100644
--- a/rust/macros/module.rs
+++ b/rust/macros/module.rs
@@ -199,103 +199,129 @@ pub(crate) fn module(ts: TokenStream) -> TokenStream {
/// Used by the printing macros, e.g. [`info!`].
const __LOG_PREFIX: &[u8] = b\"{name}\\0\";
- /// The \"Rust loadable module\" mark.
- //
- // This may be best done another way later on, e.g. as a new modinfo
- // key or a new section. For the moment, keep it simple.
- #[cfg(MODULE)]
- #[doc(hidden)]
- #[used]
- static __IS_RUST_MODULE: () = ();
-
- static mut __MOD: Option<{type_}> = None;
-
- // SAFETY: `__this_module` is constructed by the kernel at load time and will not be
- // freed until the module is unloaded.
- #[cfg(MODULE)]
- static THIS_MODULE: kernel::ThisModule = unsafe {{
- kernel::ThisModule::from_ptr(&kernel::bindings::__this_module as *const _ as *mut _)
- }};
- #[cfg(not(MODULE))]
- static THIS_MODULE: kernel::ThisModule = unsafe {{
- kernel::ThisModule::from_ptr(core::ptr::null_mut())
- }};
-
- // Loadable modules need to export the `{{init,cleanup}}_module` identifiers.
- /// # Safety
- ///
- /// This function must not be called after module initialization, because it may be
- /// freed after that completes.
- #[cfg(MODULE)]
- #[doc(hidden)]
- #[no_mangle]
- #[link_section = \".init.text\"]
- pub unsafe extern \"C\" fn init_module() -> core::ffi::c_int {{
- __init()
- }}
+ // Double nested modules, since then nobody can access the public items inside.
+ mod __module_init {{
+ mod __module_init {{
+ use super::super::{type_};
+
+ /// The \"Rust loadable module\" mark.
+ //
+ // This may be best done another way later on, e.g. as a new modinfo
+ // key or a new section. For the moment, keep it simple.
+ #[cfg(MODULE)]
+ #[doc(hidden)]
+ #[used]
+ static __IS_RUST_MODULE: () = ();
+
+ static mut __MOD: Option<{type_}> = None;
+
+ // SAFETY: `__this_module` is constructed by the kernel at load time and will not be
+ // freed until the module is unloaded.
+ #[cfg(MODULE)]
+ static THIS_MODULE: kernel::ThisModule = unsafe {{
+ kernel::ThisModule::from_ptr(&kernel::bindings::__this_module as *const _ as *mut _)
+ }};
+ #[cfg(not(MODULE))]
+ static THIS_MODULE: kernel::ThisModule = unsafe {{
+ kernel::ThisModule::from_ptr(core::ptr::null_mut())
+ }};
+
+ // Loadable modules need to export the `{{init,cleanup}}_module` identifiers.
+ /// # Safety
+ ///
+ /// This function must not be called after module initialization, because it may be
+ /// freed after that completes.
+ #[cfg(MODULE)]
+ #[doc(hidden)]
+ #[no_mangle]
+ #[link_section = \".init.text\"]
+ pub unsafe extern \"C\" fn init_module() -> core::ffi::c_int {{
+ __init()
+ }}
- #[cfg(MODULE)]
- #[doc(hidden)]
- #[no_mangle]
- pub extern \"C\" fn cleanup_module() {{
- __exit()
- }}
+ #[cfg(MODULE)]
+ #[doc(hidden)]
+ #[no_mangle]
+ pub extern \"C\" fn cleanup_module() {{
+ __exit()
+ }}
- // Built-in modules are initialized through an initcall pointer
- // and the identifiers need to be unique.
- #[cfg(not(MODULE))]
- #[cfg(not(CONFIG_HAVE_ARCH_PREL32_RELOCATIONS))]
- #[doc(hidden)]
- #[link_section = \"{initcall_section}\"]
- #[used]
- pub static __{name}_initcall: extern \"C\" fn() -> core::ffi::c_int = __{name}_init;
-
- #[cfg(not(MODULE))]
- #[cfg(CONFIG_HAVE_ARCH_PREL32_RELOCATIONS)]
- core::arch::global_asm!(
- r#\".section \"{initcall_section}\", \"a\"
- __{name}_initcall:
- .long __{name}_init - .
- .previous
- \"#
- );
+ // Built-in modules are initialized through an initcall pointer
+ // and the identifiers need to be unique.
+ #[cfg(not(MODULE))]
+ #[cfg(not(CONFIG_HAVE_ARCH_PREL32_RELOCATIONS))]
+ #[doc(hidden)]
+ #[link_section = \"{initcall_section}\"]
+ #[used]
+ pub static __{name}_initcall: extern \"C\" fn() -> core::ffi::c_int = __{name}_init;
+
+ #[cfg(not(MODULE))]
+ #[cfg(CONFIG_HAVE_ARCH_PREL32_RELOCATIONS)]
+ core::arch::global_asm!(
+ r#\".section \"{initcall_section}\", \"a\"
+ __{name}_initcall:
+ .long __{name}_init - .
+ .previous
+ \"#
+ );
+
+ #[cfg(not(MODULE))]
+ #[doc(hidden)]
+ #[no_mangle]
+ pub extern \"C\" fn __{name}_init() -> core::ffi::c_int {{
+ __init()
+ }}
- #[cfg(not(MODULE))]
- #[doc(hidden)]
- #[no_mangle]
- pub extern \"C\" fn __{name}_init() -> core::ffi::c_int {{
- __init()
- }}
+ #[cfg(not(MODULE))]
+ #[doc(hidden)]
+ #[no_mangle]
+ pub extern \"C\" fn __{name}_exit() {{
+ __exit()
+ }}
- #[cfg(not(MODULE))]
- #[doc(hidden)]
- #[no_mangle]
- pub extern \"C\" fn __{name}_exit() {{
- __exit()
- }}
+ /// # Safety
+ ///
+ /// This function must
+ /// - only be called once,
+ /// - not be called concurrently with `__exit`.
+ unsafe fn __init() -> core::ffi::c_int {{
+ match <{type_} as kernel::Module>::init(&THIS_MODULE) {{
+ Ok(m) => {{
+ // SAFETY:
+ // no data race, since `__MOD` can only be accessed by this module and
+ // there only `__init` and `__exit` access it. These functions are only
+ // called once and `__exit` cannot be called before or during `__init`.
+ unsafe {{
+ __MOD = Some(m);
+ }}
+ return 0;
+ }}
+ Err(e) => {{
+ return e.to_errno();
+ }}
+ }}
+ }}
- fn __init() -> core::ffi::c_int {{
- match <{type_} as kernel::Module>::init(&THIS_MODULE) {{
- Ok(m) => {{
+ /// # Safety
+ ///
+ /// This function must
+ /// - only be called once,
+ /// - be called after `__init`,
+ /// - not be called concurrently with `__init`.
+ unsafe fn __exit() {{
+ // SAFETY:
+ // no data race, since `__MOD` can only be accessed by this module and there
+ // only `__init` and `__exit` access it. These functions are only called once
+ // and `__init` was already called.
unsafe {{
- __MOD = Some(m);
+ // Invokes `drop()` on `__MOD`, which should be used for cleanup.
+ __MOD = None;
}}
- return 0;
}}
- Err(e) => {{
- return e.to_errno();
- }}
- }}
- }}
- fn __exit() {{
- unsafe {{
- // Invokes `drop()` on `__MOD`, which should be used for cleanup.
- __MOD = None;
+ {modinfo}
}}
}}
-
- {modinfo}
",
type_ = info.type_,
name = info.name,
base-commit: 4cece764965020c22cff7665b18a012006359095
--
2.44.0
commit 27f58c04a8f4 ("scsi: sg: Avoid sg device teardown race")
introduced an incorrect WARN_ON_ONCE() and missed a sequence where
sg_device_destroy() was used after scsi_device_put().
sg_device_destroy() is accessing the parent scsi_device request_queue which
will already be set to NULL when the preceding call to scsi_device_put()
removed the last reference to the parent scsi_device.
Drop the incorrect WARN_ON_ONCE() - allowing more than one concurrent
access to the sg device - and make sure sg_device_destroy() is not used
after scsi_device_put() in the error handling.
Link: https://lore.kernel.org/all/5375B275-D137-4D5F-BE25-6AF8ACAE41EF@linux.ibm.…
Fixes: 27f58c04a8f4 ("scsi: sg: Avoid sg device teardown race")
Cc: stable(a)vger.kernel.org
Signed-off-by: Alexander Wetzel <Alexander(a)wetzel-home.de>
---
Changes compared to V1: fixed commit message
The WARN_ON_ONCE() was kind of stupid to add:
We get add reference for each sg_open(). So opening a second session and
then closing either one will trigger the warning... Nothing to warn
about here.
Alexander
---
drivers/scsi/sg.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/scsi/sg.c b/drivers/scsi/sg.c
index 386981c6976a..833c9277419b 100644
--- a/drivers/scsi/sg.c
+++ b/drivers/scsi/sg.c
@@ -372,8 +372,9 @@ sg_open(struct inode *inode, struct file *filp)
error_out:
scsi_autopm_put_device(sdp->device);
sdp_put:
+ kref_put(&sdp->d_ref, sg_device_destroy);
scsi_device_put(sdp->device);
- goto sg_put;
+ return retval;
}
/* Release resources associated with a successful sg_open()
@@ -2233,7 +2234,6 @@ sg_remove_sfp_usercontext(struct work_struct *work)
"sg_remove_sfp: sfp=0x%p\n", sfp));
kfree(sfp);
- WARN_ON_ONCE(kref_read(&sdp->d_ref) != 1);
kref_put(&sdp->d_ref, sg_device_destroy);
scsi_device_put(device);
module_put(THIS_MODULE);
--
2.44.0
When rt_mutex_setprio changes a task's scheduling class to RT,
sometimes the task's vruntime is not updated correctly upon
return to the fair class.
Specifically, the following is being observed:
- task has just been created and running for a short time
- task sleep while still in the fair class
- task is boosted to RT via rt_mutex_setprio, which changes
the task to RT and calls check_class_changed.
- check_class_changed leads to detach_task_cfs_rq, at which point
the vruntime_normalized check sees that the task's sum_exec_runtime
is zero, which results in skipping the subtraction of the
rq's min_vruntime from the task's vruntime
- later, when the prio is deboosted and the task is moved back
to the fair class, the fair rq's min_vruntime is added to
the task's vruntime, even though it wasn't subtracted earlier.
Since the task's vruntime is about double that of other tasks in cfs_rq,
the task to be unable to run for a long time when there are continuous
runnable tasks in cfs_rq.
The immediate result is inflation of the task's vruntime, giving
it lower priority (starving it if there's enough available work).
The longer-term effect is inflation of all vruntimes because the
task's vruntime becomes the rq's min_vruntime when the higher
priority tasks go idle. That leads to a vicious cycle, where
the vruntime inflation repeatedly doubled.
The root cause of the problem is that the vruntime_normalized made a
misjudgment. Since the sum_exec_runtime of some tasks that were just
created and run for a short time is zero, the vruntime_normalized
mistakenly thinks that they are tasks that have just been forked.
Therefore, sum_exec_runtime is not subtracted from the vruntime of the
task.
So, we fix this bug by adding a check condition for newly forked task.
Signed-off-by: mingyang.cui <mingyang.cui(a)horizon.ai>
---
kernel/sched/fair.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 73a89fbd81be..3d0c14f3731f 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -11112,7 +11112,7 @@ static inline bool vruntime_normalized(struct task_struct *p)
* - A task which has been woken up by try_to_wake_up() and
* waiting for actually being woken up by sched_ttwu_pending().
*/
- if (!se->sum_exec_runtime ||
+ if (!se->sum_exec_runtime && p->state == TASK_NEW ||
(p->state == TASK_WAKING && p->sched_remote_wakeup))
return true;
--
2.34.1
Do the same check for direct io-wq execution for multishot requests that
commit 2a975d426c82 did for the inline execution, and disable multishot
mode (and revert to single shot) if the file type doesn't support NOWAIT,
and isn't opened in O_NONBLOCK mode. For multishot to work properly, it's
a requirement that nonblocking read attempts can be done.
Cc: stable(a)vger.kernel.org
Signed-off-by: Jens Axboe <axboe(a)kernel.dk>
---
io_uring/io_uring.c | 13 +++++++++----
1 file changed, 9 insertions(+), 4 deletions(-)
diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c
index 5d4b448fdc50..8baf8afb79c2 100644
--- a/io_uring/io_uring.c
+++ b/io_uring/io_uring.c
@@ -1982,10 +1982,15 @@ void io_wq_submit_work(struct io_wq_work *work)
err = -EBADFD;
if (!io_file_can_poll(req))
goto fail;
- err = -ECANCELED;
- if (io_arm_poll_handler(req, issue_flags) != IO_APOLL_OK)
- goto fail;
- return;
+ if (req->file->f_flags & O_NONBLOCK ||
+ req->file->f_mode & FMODE_NOWAIT) {
+ err = -ECANCELED;
+ if (io_arm_poll_handler(req, issue_flags) != IO_APOLL_OK)
+ goto fail;
+ return;
+ } else {
+ req->flags &= ~REQ_F_APOLL_MULTISHOT;
+ }
}
if (req->flags & REQ_F_FORCE_ASYNC) {
--
2.43.0
Supporting multishot reads requires support for NOWAIT, as the
alternative would be always having io-wq execute the work item whenever
the poll readiness triggered. Any fast file type will have NOWAIT
support (eg it understands both O_NONBLOCK and IOCB_NOWAIT). If the
given file type does not, then simply resort to single shot execution.
Cc: stable(a)vger.kernel.org
Fixes: fc68fcda04910 ("io_uring/rw: add support for IORING_OP_READ_MULTISHOT")
Signed-off-by: Jens Axboe <axboe(a)kernel.dk>
---
io_uring/rw.c | 9 ++++++++-
1 file changed, 8 insertions(+), 1 deletion(-)
diff --git a/io_uring/rw.c b/io_uring/rw.c
index 0585ebcc9773..c8d48287439e 100644
--- a/io_uring/rw.c
+++ b/io_uring/rw.c
@@ -936,6 +936,13 @@ int io_read_mshot(struct io_kiocb *req, unsigned int issue_flags)
ret = __io_read(req, issue_flags);
+ /*
+ * If the file doesn't support proper NOWAIT, then disable multishot
+ * and stay in single shot mode.
+ */
+ if (!io_file_supports_nowait(req))
+ req->flags &= ~REQ_F_APOLL_MULTISHOT;
+
/*
* If we get -EAGAIN, recycle our buffer and just let normal poll
* handling arm it.
@@ -955,7 +962,7 @@ int io_read_mshot(struct io_kiocb *req, unsigned int issue_flags)
/*
* Any successful return value will keep the multishot read armed.
*/
- if (ret > 0) {
+ if (ret > 0 && req->flags & REQ_F_APOLL_MULTISHOT) {
/*
* Put our buffer and post a CQE. If we fail to post a CQE, then
* jump to the termination path. This request is then done.
--
2.43.0
The patch below does not apply to the 4.19-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable(a)vger.kernel.org>.
To reproduce the conflict and resubmit, you may use the following commands:
git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-4.19.y
git checkout FETCH_HEAD
git cherry-pick -x 80ba43e9f799cbdd83842fc27db667289b3150f5
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2024040157-entrench-clicker-d3df@gregkh' --subject-prefix 'PATCH 4.19.y' HEAD^..
Possible dependencies:
80ba43e9f799 ("USB: core: Fix deadlock in usb_deauthorize_interface()")
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 80ba43e9f799cbdd83842fc27db667289b3150f5 Mon Sep 17 00:00:00 2001
From: Alan Stern <stern(a)rowland.harvard.edu>
Date: Tue, 12 Mar 2024 11:48:23 -0400
Subject: [PATCH] USB: core: Fix deadlock in usb_deauthorize_interface()
Among the attribute file callback routines in
drivers/usb/core/sysfs.c, the interface_authorized_store() function is
the only one which acquires a device lock on an ancestor device: It
calls usb_deauthorize_interface(), which locks the interface's parent
USB device.
The will lead to deadlock if another process already owns that lock
and tries to remove the interface, whether through a configuration
change or because the device has been disconnected. As part of the
removal procedure, device_del() waits for all ongoing sysfs attribute
callbacks to complete. But usb_deauthorize_interface() can't complete
until the device lock has been released, and the lock won't be
released until the removal has finished.
The mechanism provided by sysfs to prevent this kind of deadlock is
to use the sysfs_break_active_protection() function, which tells sysfs
not to wait for the attribute callback.
Reported-and-tested by: Yue Sun <samsun1006219(a)gmail.com>
Reported by: xingwei lee <xrivendell7(a)gmail.com>
Signed-off-by: Alan Stern <stern(a)rowland.harvard.edu>
Link: https://lore.kernel.org/linux-usb/CAEkJfYO6jRVC8Tfrd_R=cjO0hguhrV31fDPrLrNO…
Fixes: 310d2b4124c0 ("usb: interface authorization: SysFS part of USB interface authorization")
Cc: stable(a)vger.kernel.org
Link: https://lore.kernel.org/r/1c37eea1-9f56-4534-b9d8-b443438dc869@rowland.harv…
Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org>
diff --git a/drivers/usb/core/sysfs.c b/drivers/usb/core/sysfs.c
index f98263e21c2a..d83231d6736a 100644
--- a/drivers/usb/core/sysfs.c
+++ b/drivers/usb/core/sysfs.c
@@ -1217,14 +1217,24 @@ static ssize_t interface_authorized_store(struct device *dev,
{
struct usb_interface *intf = to_usb_interface(dev);
bool val;
+ struct kernfs_node *kn;
if (kstrtobool(buf, &val) != 0)
return -EINVAL;
- if (val)
+ if (val) {
usb_authorize_interface(intf);
- else
- usb_deauthorize_interface(intf);
+ } else {
+ /*
+ * Prevent deadlock if another process is concurrently
+ * trying to unregister intf.
+ */
+ kn = sysfs_break_active_protection(&dev->kobj, &attr->attr);
+ if (kn) {
+ usb_deauthorize_interface(intf);
+ sysfs_unbreak_active_protection(kn);
+ }
+ }
return count;
}