On Fri, 2023-07-21 at 13:19 +0800, Will Shiu wrote: > As following backtrace, the struct file_lock request , in posix_lock_inode > is free before ftrace function using. > Replace the ftrace function ahead free flow could fix the use-after-free > issue. > > [name:report&]=============================================== > BUG:KASAN: use-after-free in trace_event_raw_event_filelock_lock+0x80/0x12c > [name:report&]Read at addr f6ffff8025622620 by task NativeThread/16753 > [name:report_hw_tags&]Pointer tag: [f6], memory tag: [fe] > [name:report&] > BT: > Hardware name: MT6897 (DT) > Call trace: > dump_backtrace+0xf8/0x148 > show_stack+0x18/0x24 > dump_stack_lvl+0x60/0x7c > print_report+0x2c8/0xa08 > kasan_report+0xb0/0x120 > __do_kernel_fault+0xc8/0x248 > do_bad_area+0x30/0xdc > do_tag_check_fault+0x1c/0x30 > do_mem_abort+0x58/0xbc > el1_abort+0x3c/0x5c > el1h_64_sync_handler+0x54/0x90 > el1h_64_sync+0x68/0x6c > trace_event_raw_event_filelock_lock+0x80/0x12c > posix_lock_inode+0xd0c/0xd60 > do_lock_file_wait+0xb8/0x190 > fcntl_setlk+0x2d8/0x440 > ... > [name:report&] > [name:report&]Allocated by task 16752: > ... > slab_post_alloc_hook+0x74/0x340 > kmem_cache_alloc+0x1b0/0x2f0 > posix_lock_inode+0xb0/0xd60 > ... > [name:report&] > [name:report&]Freed by task 16752: > ... > kmem_cache_free+0x274/0x5b0 > locks_dispose_list+0x3c/0x148 > posix_lock_inode+0xc40/0xd60 > do_lock_file_wait+0xb8/0x190 > fcntl_setlk+0x2d8/0x440 > do_fcntl+0x150/0xc18 > ... > > Signed-off-by: Will Shiu <Will.Shiu@xxxxxxxxxxxx> > --- > fs/locks.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/fs/locks.c b/fs/locks.c > index df8b26a42524..a552bdb6badc 100644 > --- a/fs/locks.c > +++ b/fs/locks.c > @@ -1301,6 +1301,7 @@ static int posix_lock_inode(struct inode *inode, struct file_lock *request, > out: > spin_unlock(&ctx->flc_lock); > percpu_up_read(&file_rwsem); > + trace_posix_lock_inode(inode, request, error); > /* > * Free any unused locks. > */ > @@ -1309,7 +1310,6 @@ static int posix_lock_inode(struct inode *inode, struct file_lock *request, > if (new_fl2) > locks_free_lock(new_fl2); > locks_dispose_list(&dispose); > - trace_posix_lock_inode(inode, request, error); > > return error; > } Could you send along the entire KASAN log message? I'm not sure I see how this is being tripped. The lock we're passing in here is "request" and that shouldn't be freed since it's allocated and owned by the caller. -- Jeff Layton <jlayton@xxxxxxxxxx>
