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    Subject[28/38] exec: do not call request_module() twice from search_binary_handler()
    3.0-stable review patch.  If anyone has any objections, please let us know.


    From: Tetsuo Handa <>

    commit 912193521b719fbfc2f16776febf5232fe8ba261 upstream.

    Currently, search_binary_handler() tries to load binary loader module
    using request_module() if a loader for the requested program is not yet
    loaded. But second attempt of request_module() does not affect the result
    of search_binary_handler().

    If request_module() triggered recursion, calling request_module() twice
    causes 2 to the power of MAX_KMOD_CONCURRENT (= 50) repetitions. It is
    not an infinite loop but is sufficient for users to consider as a hang up.

    Therefore, this patch changes not to call request_module() twice, making 1
    to the power of MAX_KMOD_CONCURRENT repetitions in case of recursion.

    Signed-off-by: Tetsuo Handa <>
    Reported-by: Richard Weinberger <>
    Tested-by: Richard Weinberger <>
    Cc: Al Viro <>
    Signed-off-by: Andrew Morton <>
    Cc: Maxim Uvarov <>
    Signed-off-by: Linus Torvalds <>

    fs/exec.c | 2 ++
    1 file changed, 2 insertions(+)

    --- a/fs/exec.c
    +++ b/fs/exec.c
    @@ -1411,6 +1411,8 @@ int search_binary_handler(struct linux_b
    printable(bprm->buf[2]) &&
    break; /* -ENOEXEC */
    + if (try)
    + break; /* -ENOEXEC */
    request_module("binfmt-%04x", *(unsigned short *)(&bprm->buf[2]));

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      Last update: 2011-10-11 19:07    [W:0.020 / U:8.388 seconds]
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