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    SubjectRe: [PATCH v2] kdb: Use strscpy with destination buffer size
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    On 20/09/2018 13:59, Prarit Bhargava wrote:
    > gcc 8.1.0 warns with:
    >
    > kernel/debug/kdb/kdb_support.c: In function ‘kallsyms_symbol_next’:
    > kernel/debug/kdb/kdb_support.c:239:4: warning: ‘strncpy’ specified bound depends on the length of the source argument [-Wstringop-overflow=]
    > strncpy(prefix_name, name, strlen(name)+1);
    > ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    > kernel/debug/kdb/kdb_support.c:239:31: note: length computed here
    >
    > Use strscpy() with the destination buffer size, and use ellipses when
    > displaying truncated symbols.
    >
    > v2: Use strscpy()
    >
    > Signed-off-by: Prarit Bhargava <prarit@redhat.com>
    > Cc: Jonathan Toppins <jtoppins@redhat.com>
    > Cc: Jason Wessel <jason.wessel@windriver.com>
    > Cc: Daniel Thompson <daniel.thompson@linaro.org>
    > Cc: kgdb-bugreport@lists.sourceforge.net
    > ---
    > kernel/debug/kdb/kdb_io.c | 15 +++++++++------
    > kernel/debug/kdb/kdb_private.h | 2 +-
    > kernel/debug/kdb/kdb_support.c | 10 +++++-----
    > 3 files changed, 15 insertions(+), 12 deletions(-)
    >
    > diff --git a/kernel/debug/kdb/kdb_io.c b/kernel/debug/kdb/kdb_io.c
    > index ed5d34925ad0..6a4b41484afe 100644
    > --- a/kernel/debug/kdb/kdb_io.c
    > +++ b/kernel/debug/kdb/kdb_io.c
    > @@ -216,7 +216,7 @@ static char *kdb_read(char *buffer, size_t bufsize)
    > int count;
    > int i;
    > int diag, dtab_count;
    > - int key;
    > + int key, buf_size, ret;
    >
    >
    > diag = kdbgetintenv("DTABCOUNT", &dtab_count);
    > @@ -336,9 +336,8 @@ static char *kdb_read(char *buffer, size_t bufsize)
    > else
    > p_tmp = tmpbuffer;
    > len = strlen(p_tmp);
    > - count = kallsyms_symbol_complete(p_tmp,
    > - sizeof(tmpbuffer) -
    > - (p_tmp - tmpbuffer));
    > + buf_size = sizeof(tmpbuffer) - (p_tmp - tmpbuffer);
    > + count = kallsyms_symbol_complete(p_tmp, buf_size);
    > if (tab == 2 && count > 0) {
    > kdb_printf("\n%d symbols are found.", count);
    > if (count > dtab_count) {
    > @@ -350,9 +349,13 @@ static char *kdb_read(char *buffer, size_t bufsize)
    > }
    > kdb_printf("\n");
    > for (i = 0; i < count; i++) {
    > - if (WARN_ON(!kallsyms_symbol_next(p_tmp, i)))
    > + ret = kallsyms_symbol_next(p_tmp, i, buf_size);
    > + if (WARN_ON(!ret))
    > break;
    I'm getting confused by having two different branches on ret.

    Don't get a WARN_ON() when ret == -E2BIG?


    Daniel.


    > - kdb_printf("%s ", p_tmp);
    > + if (ret != -E2BIG)
    > + kdb_printf("%s ", p_tmp);
    > + else
    > + kdb_printf("%s... ", p_tmp);
    > *(p_tmp + len) = '\0';
    > }
    > if (i >= dtab_count)

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