diff options
| author | Waiman Long <longman@redhat.com> | 2025-08-11 10:11:47 -0400 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2025-08-20 18:41:35 +0200 |
| commit | 6b3942f8b0851dab63d685c5e0609b172cc43407 (patch) | |
| tree | 32337bc2e962be8bda400ea35bee5bc0dff5c6e1 | |
| parent | f43a9420e195cc63d120cba654baaab2a2bc6c9a (diff) | |
futex: Use user_write_access_begin/_end() in futex_put_value()
commit dfb36e4a8db0cd56f92d4cb445f54e85a9b40897 upstream.
Commit cec199c5e39b ("futex: Implement FUTEX2_NUMA") introduced the
futex_put_value() helper to write a value to the given user
address.
However, it uses user_read_access_begin() before the write. For
architectures that differentiate between read and write accesses, like
PowerPC, futex_put_value() fails with -EFAULT.
Fix that by using the user_write_access_begin/user_write_access_end() pair
instead.
Fixes: cec199c5e39b ("futex: Implement FUTEX2_NUMA")
Signed-off-by: Waiman Long <longman@redhat.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/all/20250811141147.322261-1-longman@redhat.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | kernel/futex/futex.h | 6 |
1 files changed, 3 insertions, 3 deletions
diff --git a/kernel/futex/futex.h b/kernel/futex/futex.h index fcd1617212ee..e3fecc2311ab 100644 --- a/kernel/futex/futex.h +++ b/kernel/futex/futex.h @@ -321,13 +321,13 @@ static __always_inline int futex_put_value(u32 val, u32 __user *to) { if (can_do_masked_user_access()) to = masked_user_access_begin(to); - else if (!user_read_access_begin(to, sizeof(*to))) + else if (!user_write_access_begin(to, sizeof(*to))) return -EFAULT; unsafe_put_user(val, to, Efault); - user_read_access_end(); + user_write_access_end(); return 0; Efault: - user_read_access_end(); + user_write_access_end(); return -EFAULT; } |