• He Zhe's avatar
    printk: Fix panic caused by passing log_buf_len to command line · cc4dcea8
    He Zhe authored
    commit 277fcdb2 upstream.
    
    log_buf_len_setup does not check input argument before passing it to
    simple_strtoull. The argument would be a NULL pointer if "log_buf_len",
    without its value, is set in command line and thus causes the following
    panic.
    
    PANIC: early exception 0xe3 IP 10:ffffffffaaeacd0d error 0 cr2 0x0
    [    0.000000] CPU: 0 PID: 0 Comm: swapper Not tainted 4.19.0-rc4-yocto-standard+ #1
    [    0.000000] RIP: 0010:_parse_integer_fixup_radix+0xd/0x70
    ...
    [    0.000000] Call Trace:
    [    0.000000]  simple_strtoull+0x29/0x70
    [    0.000000]  memparse+0x26/0x90
    [    0.000000]  log_buf_len_setup+0x17/0x22
    [    0.000000]  do_early_param+0x57/0x8e
    [    0.000000]  parse_args+0x208/0x320
    [    0.000000]  ? rdinit_setup+0x30/0x30
    [    0.000000]  parse_early_options+0x29/0x2d
    [    0.000000]  ? rdinit_setup+0x30/0x30
    [    0.000000]  parse_early_param+0x36/0x4d
    [    0.000000]  setup_arch+0x336/0x99e
    [    0.000000]  start_kernel+0x6f/0x4ee
    [    0.000000]  x86_64_start_reservations+0x24/0x26
    [    0.000000]  x86_64_start_kernel+0x6f/0x72
    [    0.000000]  secondary_startup_64+0xa4/0xb0
    
    This patch adds a check to prevent the panic.
    
    Link: http://lkml.kernel.org/r/1538239553-81805-1-git-send-email-zhe.he@windriver.com
    
    
    Cc: stable@vger.kernel.org
    Cc: rostedt@goodmis.org
    Cc: linux-kernel@vger.kernel.org
    Signed-off-by: default avatarHe Zhe <zhe.he@windriver.com>
    Reviewed-by: default avatarSergey Senozhatsky <sergey.senozhatsky@gmail.com>
    Signed-off-by: default avatarPetr Mladek <pmladek@suse.com>
    Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
    cc4dcea8
printk.c 79.6 KB