diff options
| author | Alice Ryhl <aliceryhl@google.com> | 2025-12-02 11:24:24 +0000 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2025-12-29 11:34:16 +0100 |
| commit | 361e0ff456a8daf9753c18030533256e4133ce7a (patch) | |
| tree | 77748e5ab66ff1985b3cebe2a3b34fe9215e7f3d | |
| parent | 420f423defcf6d0af2263d38da870ca4a20c0990 (diff) | |
rust_binder: remove spin_lock() in rust_shrink_free_page()
When forward-porting Rust Binder to 6.18, I neglected to take commit
fb56fdf8b9a2 ("mm/list_lru: split the lock to per-cgroup scope") into
account, and apparently I did not end up running the shrinker callback
when I sanity tested the driver before submission. This leads to crashes
like the following:
============================================
WARNING: possible recursive locking detected
6.18.0-mainline-maybe-dirty #1 Tainted: G IO
--------------------------------------------
kswapd0/68 is trying to acquire lock:
ffff956000fa18b0 (&l->lock){+.+.}-{2:2}, at: lock_list_lru_of_memcg+0x128/0x230
but task is already holding lock:
ffff956000fa18b0 (&l->lock){+.+.}-{2:2}, at: rust_helper_spin_lock+0xd/0x20
other info that might help us debug this:
Possible unsafe locking scenario:
CPU0
----
lock(&l->lock);
lock(&l->lock);
*** DEADLOCK ***
May be due to missing lock nesting notation
3 locks held by kswapd0/68:
#0: ffffffff90d2e260 (fs_reclaim){+.+.}-{0:0}, at: kswapd+0x597/0x1160
#1: ffff956000fa18b0 (&l->lock){+.+.}-{2:2}, at: rust_helper_spin_lock+0xd/0x20
#2: ffffffff90cf3680 (rcu_read_lock){....}-{1:2}, at: lock_list_lru_of_memcg+0x2d/0x230
To fix this, remove the spin_lock() call from rust_shrink_free_page().
Cc: stable <stable@kernel.org>
Fixes: eafedbc7c050 ("rust_binder: add Rust Binder driver")
Signed-off-by: Alice Ryhl <aliceryhl@google.com>
Link: https://patch.msgid.link/20251202-binder-shrink-unspin-v1-1-263efb9ad625@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | drivers/android/binder/page_range.rs | 3 |
1 files changed, 0 insertions, 3 deletions
diff --git a/drivers/android/binder/page_range.rs b/drivers/android/binder/page_range.rs index 9379038f61f5..fdd97112ef5c 100644 --- a/drivers/android/binder/page_range.rs +++ b/drivers/android/binder/page_range.rs @@ -727,8 +727,5 @@ unsafe extern "C" fn rust_shrink_free_page( drop(mm); drop(page); - // SAFETY: We just unlocked the lru lock, but it should be locked when we return. - unsafe { bindings::spin_lock(&raw mut (*lru).lock) }; - LRU_REMOVED_ENTRY } |