The return value from `__rb_map_vma()`, which rejects writable or executable mappings (VM_WRITE, VM_EXEC, or !VM_MAYSHARE), was being ignored. As a result the caller of `__rb_map_vma` always returned 0 even when the mapping had actually failed, allowing it to proceed with an invalid VMA.
Reported-by: [email protected] Closes: https://syzkaller.appspot.com/bug?id=194151be8eaebd826005329b2e123aecae714bdb Signed-off-by: Ankit Khushwaha <[email protected]> --- #syz test: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git 4ff71af020ae --- kernel/trace/ring_buffer.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c index 43460949ad3f..4efb90364f48 100644 --- a/kernel/trace/ring_buffer.c +++ b/kernel/trace/ring_buffer.c @@ -7271,6 +7271,8 @@ int ring_buffer_map(struct trace_buffer *buffer, int cpu, cpu_buffer->subbuf_ids = NULL; rb_free_meta_page(cpu_buffer); atomic_dec(&cpu_buffer->resize_disabled); + /* VM failed to be mapped */ + return err; } return 0; -- 2.51.0
