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binder: fix memleak of proc->delivered_freeze

If a freeze notification is cleared with BC_CLEAR_FREEZE_NOTIFICATION
before calling binder_freeze_notification_done(), then it is detached
from its reference (e.g. ref->freeze) but the work remains queued in
proc->delivered_freeze. This leads to a memory leak when the process
exits as any pending entries in proc->delivered_freeze are not freed:

unreferenced object 0xffff38e8cfa36180 (size 64):
comm "binder-util", pid 655, jiffies 4294936641
hex dump (first 32 bytes):
b8 e9 9e c8 e8 38 ff ff b8 e9 9e c8 e8 38 ff ff .....8.......8..
0b 00 00 00 00 00 00 00 3c 1f 4b 00 00 00 00 00 ........<.K.....
backtrace (crc 95983b32):
[<000000000d0582cf>] kmemleak_alloc+0x34/0x40
[<000000009c99a513>] __kmalloc_cache_noprof+0x208/0x280
[<00000000313b1704>] binder_thread_write+0xdec/0x439c
[<000000000cbd33bb>] binder_ioctl+0x1b68/0x22cc
[<000000002bbedeeb>] __arm64_sys_ioctl+0x124/0x190
[<00000000b439adee>] invoke_syscall+0x6c/0x254
[<00000000173558fc>] el0_svc_common.constprop.0+0xac/0x230
[<0000000084f72311>] do_el0_svc+0x40/0x58
[<000000008b872457>] el0_svc+0x38/0x78
[<00000000ee778653>] el0t_64_sync_handler+0x120/0x12c
[<00000000a8ec61bf>] el0t_64_sync+0x190/0x194

This patch fixes the leak by ensuring that any pending entries in
proc->delivered_freeze are freed during binder_deferred_release().

Fixes: d579b04a52a1 ("binder: frozen notification")
Cc: stable@vger.kernel.org
Signed-off-by: Carlos Llamas <cmllamas@google.com>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Acked-by: Todd Kjos <tkjos@google.com>
Link: https://lore.kernel.org/r/20240926233632.821189-8-cmllamas@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

authored by

Carlos Llamas and committed by
Greg Kroah-Hartman
1db76ec2 ca63c669

+11
+11
drivers/android/binder.c
··· 5155 5155 } break; 5156 5156 case BINDER_WORK_NODE: 5157 5157 break; 5158 + case BINDER_WORK_CLEAR_FREEZE_NOTIFICATION: { 5159 + struct binder_ref_freeze *freeze; 5160 + 5161 + freeze = container_of(w, struct binder_ref_freeze, work); 5162 + binder_debug(BINDER_DEBUG_DEAD_TRANSACTION, 5163 + "undelivered freeze notification, %016llx\n", 5164 + (u64)freeze->cookie); 5165 + kfree(freeze); 5166 + binder_stats_deleted(BINDER_STAT_FREEZE); 5167 + } break; 5158 5168 default: 5159 5169 pr_err("unexpected work type, %d, not freed\n", 5160 5170 wtype); ··· 6283 6273 6284 6274 binder_release_work(proc, &proc->todo); 6285 6275 binder_release_work(proc, &proc->delivered_death); 6276 + binder_release_work(proc, &proc->delivered_freeze); 6286 6277 6287 6278 binder_debug(BINDER_DEBUG_OPEN_CLOSE, 6288 6279 "%s: %d threads %d, nodes %d (ref %d), refs %d, active transactions %d\n",