• Zheng Yejian's avatar
    tracing: Fix memory leak of iter->temp when reading trace_pipe · d5a82189
    Zheng Yejian authored
    kmemleak reports:
      unreferenced object 0xffff88814d14e200 (size 256):
        comm "cat", pid 336, jiffies 4294871818 (age 779.490s)
        hex dump (first 32 bytes):
          04 00 01 03 00 00 00 00 08 00 00 00 00 00 00 00  ................
          0c d8 c8 9b ff ff ff ff 04 5a ca 9b ff ff ff ff  .........Z......
        backtrace:
          [<ffffffff9bdff18f>] __kmalloc+0x4f/0x140
          [<ffffffff9bc9238b>] trace_find_next_entry+0xbb/0x1d0
          [<ffffffff9bc9caef>] trace_print_lat_context+0xaf/0x4e0
          [<ffffffff9bc94490>] print_trace_line+0x3e0/0x950
          [<ffffffff9bc95499>] tracing_read_pipe+0x2d9/0x5a0
          [<ffffffff9bf03a43>] vfs_read+0x143/0x520
          [<ffffffff9bf04c2d>] ksys_read+0xbd/0x160
          [<ffffffff9d0f0edf>] do_syscall_64+0x3f/0x90
          [<ffffffff9d2000aa>] entry_SYSCALL_64_after_hwframe+0x6e/0xd8
    
    when reading file 'trace_pipe', 'iter->temp' is allocated or relocated
    in trace_find_next_entry() but not freed before 'trace_pipe' is closed.
    
    To fix it, free 'iter->temp' in tracing_release_pipe().
    
    Link: https://lore.kernel.org/linux-trace-kernel/20230713141435.1133021-1-zhengyejian1@huawei.com
    
    Cc: stable@vger.kernel.org
    Fixes: ff895103 ("tracing: Save off entry when peeking at next entry")
    Signed-off-by: default avatarZheng Yejian <zhengyejian1@huawei.com>
    Signed-off-by: default avatarSteven Rostedt (Google) <rostedt@goodmis.org>
    d5a82189
trace.c 257 KB