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authorLiam Howlett <liam.howlett@oracle.com>2022-08-10 19:02:25 +0300
committerAndrew Morton <akpm@linux-foundation.org>2022-08-29 00:02:44 +0300
commit44e602b4e52f70f04620bbbf4fe46ecb40170bde (patch)
tree03f2ad041070e97afa57e373b6125767ace66460 /drivers/android/binder_alloc.c
parentfcab34b433e2c13e333b2f53c4a8409eadc432c7 (diff)
downloadlinux-44e602b4e52f70f04620bbbf4fe46ecb40170bde.tar.xz
binder_alloc: add missing mmap_lock calls when using the VMA
Take the mmap_read_lock() when using the VMA in binder_alloc_print_pages() and when checking for a VMA in binder_alloc_new_buf_locked(). It is worth noting binder_alloc_new_buf_locked() drops the VMA read lock after it verifies a VMA exists, but may be taken again deeper in the call stack, if necessary. Link: https://lkml.kernel.org/r/20220810160209.1630707-1-Liam.Howlett@oracle.com Fixes: a43cfc87caaf (android: binder: stop saving a pointer to the VMA) Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com> Reported-by: Ondrej Mosnacek <omosnace@redhat.com> Reported-by: <syzbot+a7b60a176ec13cafb793@syzkaller.appspotmail.com> Acked-by: Carlos Llamas <cmllamas@google.com> Tested-by: Ondrej Mosnacek <omosnace@redhat.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Christian Brauner (Microsoft) <brauner@kernel.org> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Hridya Valsaraju <hridya@google.com> Cc: Joel Fernandes <joel@joelfernandes.org> Cc: Martijn Coenen <maco@android.com> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Todd Kjos <tkjos@android.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: "Arve Hjønnevåg" <arve@android.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'drivers/android/binder_alloc.c')
-rw-r--r--drivers/android/binder_alloc.c31
1 files changed, 21 insertions, 10 deletions
diff --git a/drivers/android/binder_alloc.c b/drivers/android/binder_alloc.c
index 1014beb12802..51f4e1c5cd01 100644
--- a/drivers/android/binder_alloc.c
+++ b/drivers/android/binder_alloc.c
@@ -402,12 +402,15 @@ static struct binder_buffer *binder_alloc_new_buf_locked(
size_t size, data_offsets_size;
int ret;
+ mmap_read_lock(alloc->vma_vm_mm);
if (!binder_alloc_get_vma(alloc)) {
+ mmap_read_unlock(alloc->vma_vm_mm);
binder_alloc_debug(BINDER_DEBUG_USER_ERROR,
"%d: binder_alloc_buf, no vma\n",
alloc->pid);
return ERR_PTR(-ESRCH);
}
+ mmap_read_unlock(alloc->vma_vm_mm);
data_offsets_size = ALIGN(data_size, sizeof(void *)) +
ALIGN(offsets_size, sizeof(void *));
@@ -929,17 +932,25 @@ void binder_alloc_print_pages(struct seq_file *m,
* Make sure the binder_alloc is fully initialized, otherwise we might
* read inconsistent state.
*/
- if (binder_alloc_get_vma(alloc) != NULL) {
- for (i = 0; i < alloc->buffer_size / PAGE_SIZE; i++) {
- page = &alloc->pages[i];
- if (!page->page_ptr)
- free++;
- else if (list_empty(&page->lru))
- active++;
- else
- lru++;
- }
+
+ mmap_read_lock(alloc->vma_vm_mm);
+ if (binder_alloc_get_vma(alloc) == NULL) {
+ mmap_read_unlock(alloc->vma_vm_mm);
+ goto uninitialized;
}
+
+ mmap_read_unlock(alloc->vma_vm_mm);
+ for (i = 0; i < alloc->buffer_size / PAGE_SIZE; i++) {
+ page = &alloc->pages[i];
+ if (!page->page_ptr)
+ free++;
+ else if (list_empty(&page->lru))
+ active++;
+ else
+ lru++;
+ }
+
+uninitialized:
mutex_unlock(&alloc->mutex);
seq_printf(m, " pages: %d:%d:%d\n", active, lru, free);
seq_printf(m, " pages high watermark: %zu\n", alloc->pages_high);