lkml.org 
[lkml]   [2017]   [Sep]   [11]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Subject[PATCH] ftrace: fix kmemleak in unregister_ftrace_graph
    Date
    From: Shu Wang <shuwang@redhat.com>

    The trampoline allocated by function tracer was
    overwrite by function_graph tracer, and cause
    memory leak. The save_global_trampoline should
    save previous trampoline in register_ftrace_graph
    and restore it in unregister_ftrace_graph. But
    as it implemented, save_global_trampoline was only
    used in unregister_ftrace_graph as default value 0,
    and overwrite the previous trampoline's value.

    kmmeleak backtrace:
    kmemleak_vmalloc+0x77/0xc0
    __vmalloc_node_range+0x1b5/0x2c0
    module_alloc+0x7c/0xd0
    arch_ftrace_update_trampoline+0xb5/0x290
    ftrace_startup+0x78/0x210
    register_ftrace_function+0x8b/0xd0
    function_trace_init+0x4f/0x80
    tracing_set_tracer+0xe6/0x170
    tracing_set_trace_write+0x90/0xd0
    __vfs_write+0x37/0x170
    vfs_write+0xb2/0x1b0
    SyS_write+0x55/0xc0
    do_syscall_64+0x67/0x180
    return_from_SYSCALL_64+0x0/0x6a

    Signed-off-by: Shu Wang <shuwang@redhat.com>
    ---
    kernel/trace/ftrace.c | 14 --------------
    1 file changed, 14 deletions(-)

    diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
    index 6abfafd7f173..8319e09e15b9 100644
    --- a/kernel/trace/ftrace.c
    +++ b/kernel/trace/ftrace.c
    @@ -4954,9 +4954,6 @@ static char ftrace_graph_buf[FTRACE_FILTER_SIZE] __initdata;
    static char ftrace_graph_notrace_buf[FTRACE_FILTER_SIZE] __initdata;
    static int ftrace_graph_set_hash(struct ftrace_hash *hash, char *buffer);

    -static unsigned long save_global_trampoline;
    -static unsigned long save_global_flags;
    -
    static int __init set_graph_function(char *str)
    {
    strlcpy(ftrace_graph_buf, str, FTRACE_FILTER_SIZE);
    @@ -6808,17 +6805,6 @@ void unregister_ftrace_graph(void)
    unregister_pm_notifier(&ftrace_suspend_notifier);
    unregister_trace_sched_switch(ftrace_graph_probe_sched_switch, NULL);

    -#ifdef CONFIG_DYNAMIC_FTRACE
    - /*
    - * Function graph does not allocate the trampoline, but
    - * other global_ops do. We need to reset the ALLOC_TRAMP flag
    - * if one was used.
    - */
    - global_ops.trampoline = save_global_trampoline;
    - if (save_global_flags & FTRACE_OPS_FL_ALLOC_TRAMP)
    - global_ops.flags |= FTRACE_OPS_FL_ALLOC_TRAMP;
    -#endif
    -
    out:
    mutex_unlock(&ftrace_lock);
    }
    --
    2.13.5
    \
     
     \ /
      Last update: 2017-09-12 04:16    [W:4.174 / U:0.016 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site