| Message ID | 1420828268-10360-1-git-send-email-jtoppins@cumulusnetworks.com |
|---|---|
| State | Accepted, archived |
| Delegated to: | David Miller |
| Headers | show |
On Fri, Jan 09, 2015 at 01:31:08PM -0500, Jonathan Toppins wrote: > Remove the empty array element initializer and size the array with > BOND_OPT_LAST so the compiler will complain if more elements are in > there than should be. > > An interesting unwanted side effect of this initializer is that if one > inserts new options into the middle of the array then this initializer > will zero out the option that equals BOND_OPT_TLB_DYNAMIC_LB+1. > > Example: > Extend the OPTS enum: > enum { > ... > BOND_OPT_TLB_DYNAMIC_LB, > BOND_OPT_LACP_NEW1, > BOND_OPT_LAST > }; > > Now insert into bond_opts array: > static const struct bond_option bond_opts[] = { > ... > [BOND_OPT_LACP_RATE] = { .... unchanged stuff .... }, > [BOND_OPT_LACP_NEW1] = { ... new stuff ... }, > ... > [BOND_OPT_TLB_DYNAMIC_LB] = { .... unchanged stuff ....}, > { } // MARK A > }; > > Since BOND_OPT_LACP_NEW1 = BOND_OPT_TLB_DYNAMIC_LB+1, the last > initializer (MARK A) will overwrite the contents of BOND_OPT_LACP_NEW1 > and can be easily viewed with the crash utility. > > Signed-off-by: Jonathan Toppins <jtoppins@cumulusnetworks.com> > Cc: Andy Gospodarek <gospo@cumulusnetworks.com> > Cc: Nikolay Aleksandrov <nikolay@redhat.com> I do not recall if there was a specific reason that Nik added this, so presuming there was not.... Signed-off-by: Andy Gospodarek <gospo@cumulusnetworks.com> > --- > drivers/net/bonding/bond_options.c | 5 ++--- > 1 file changed, 2 insertions(+), 3 deletions(-) > > diff --git a/drivers/net/bonding/bond_options.c b/drivers/net/bonding/bond_options.c > index 1a61cc9..9bd538d4 100644 > --- a/drivers/net/bonding/bond_options.c > +++ b/drivers/net/bonding/bond_options.c > @@ -186,7 +186,7 @@ static const struct bond_opt_value bond_tlb_dynamic_lb_tbl[] = { > { NULL, -1, 0} > }; > > -static const struct bond_option bond_opts[] = { > +static const struct bond_option bond_opts[BOND_OPT_LAST] = { > [BOND_OPT_MODE] = { > .id = BOND_OPT_MODE, > .name = "mode", > @@ -379,8 +379,7 @@ static const struct bond_option bond_opts[] = { > .values = bond_tlb_dynamic_lb_tbl, > .flags = BOND_OPTFLAG_IFDOWN, > .set = bond_option_tlb_dynamic_lb_set, > - }, > - { } > + } > }; > > /* Searches for an option by name */ > -- > 1.7.10.4 > -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On 09/01/15 19:48, Andy Gospodarek wrote: > On Fri, Jan 09, 2015 at 01:31:08PM -0500, Jonathan Toppins wrote: >> Remove the empty array element initializer and size the array with >> BOND_OPT_LAST so the compiler will complain if more elements are in >> there than should be. >> >> An interesting unwanted side effect of this initializer is that if one >> inserts new options into the middle of the array then this initializer >> will zero out the option that equals BOND_OPT_TLB_DYNAMIC_LB+1. >> >> Example: >> Extend the OPTS enum: >> enum { >> ... >> BOND_OPT_TLB_DYNAMIC_LB, >> BOND_OPT_LACP_NEW1, >> BOND_OPT_LAST >> }; >> >> Now insert into bond_opts array: >> static const struct bond_option bond_opts[] = { >> ... >> [BOND_OPT_LACP_RATE] = { .... unchanged stuff .... }, >> [BOND_OPT_LACP_NEW1] = { ... new stuff ... }, >> ... >> [BOND_OPT_TLB_DYNAMIC_LB] = { .... unchanged stuff ....}, >> { } // MARK A >> }; >> >> Since BOND_OPT_LACP_NEW1 = BOND_OPT_TLB_DYNAMIC_LB+1, the last >> initializer (MARK A) will overwrite the contents of BOND_OPT_LACP_NEW1 >> and can be easily viewed with the crash utility. >> >> Signed-off-by: Jonathan Toppins <jtoppins@cumulusnetworks.com> >> Cc: Andy Gospodarek <gospo@cumulusnetworks.com> >> Cc: Nikolay Aleksandrov <nikolay@redhat.com> > > I do not recall if there was a specific reason that Nik added this, so > presuming there was not.... > > Signed-off-by: Andy Gospodarek <gospo@cumulusnetworks.com> > Indeed, it's an oversight on my part from a previous version of the opts patch-set which used a different end-of-array indicator :-) Acked-by: Nikolay Aleksandrov <nikolay@redhat.com> -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
From: Jonathan Toppins <jtoppins@cumulusnetworks.com> Date: Fri, 9 Jan 2015 13:31:08 -0500 > Remove the empty array element initializer and size the array with > BOND_OPT_LAST so the compiler will complain if more elements are in > there than should be. > > An interesting unwanted side effect of this initializer is that if one > inserts new options into the middle of the array then this initializer > will zero out the option that equals BOND_OPT_TLB_DYNAMIC_LB+1. > > Example: > Extend the OPTS enum: > enum { > ... > BOND_OPT_TLB_DYNAMIC_LB, > BOND_OPT_LACP_NEW1, > BOND_OPT_LAST > }; > > Now insert into bond_opts array: > static const struct bond_option bond_opts[] = { > ... > [BOND_OPT_LACP_RATE] = { .... unchanged stuff .... }, > [BOND_OPT_LACP_NEW1] = { ... new stuff ... }, > ... > [BOND_OPT_TLB_DYNAMIC_LB] = { .... unchanged stuff ....}, > { } // MARK A > }; > > Since BOND_OPT_LACP_NEW1 = BOND_OPT_TLB_DYNAMIC_LB+1, the last > initializer (MARK A) will overwrite the contents of BOND_OPT_LACP_NEW1 > and can be easily viewed with the crash utility. > > Signed-off-by: Jonathan Toppins <jtoppins@cumulusnetworks.com> Applied. -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/drivers/net/bonding/bond_options.c b/drivers/net/bonding/bond_options.c index 1a61cc9..9bd538d4 100644 --- a/drivers/net/bonding/bond_options.c +++ b/drivers/net/bonding/bond_options.c @@ -186,7 +186,7 @@ static const struct bond_opt_value bond_tlb_dynamic_lb_tbl[] = { { NULL, -1, 0} }; -static const struct bond_option bond_opts[] = { +static const struct bond_option bond_opts[BOND_OPT_LAST] = { [BOND_OPT_MODE] = { .id = BOND_OPT_MODE, .name = "mode", @@ -379,8 +379,7 @@ static const struct bond_option bond_opts[] = { .values = bond_tlb_dynamic_lb_tbl, .flags = BOND_OPTFLAG_IFDOWN, .set = bond_option_tlb_dynamic_lb_set, - }, - { } + } }; /* Searches for an option by name */
Remove the empty array element initializer and size the array with BOND_OPT_LAST so the compiler will complain if more elements are in there than should be. An interesting unwanted side effect of this initializer is that if one inserts new options into the middle of the array then this initializer will zero out the option that equals BOND_OPT_TLB_DYNAMIC_LB+1. Example: Extend the OPTS enum: enum { ... BOND_OPT_TLB_DYNAMIC_LB, BOND_OPT_LACP_NEW1, BOND_OPT_LAST }; Now insert into bond_opts array: static const struct bond_option bond_opts[] = { ... [BOND_OPT_LACP_RATE] = { .... unchanged stuff .... }, [BOND_OPT_LACP_NEW1] = { ... new stuff ... }, ... [BOND_OPT_TLB_DYNAMIC_LB] = { .... unchanged stuff ....}, { } // MARK A }; Since BOND_OPT_LACP_NEW1 = BOND_OPT_TLB_DYNAMIC_LB+1, the last initializer (MARK A) will overwrite the contents of BOND_OPT_LACP_NEW1 and can be easily viewed with the crash utility. Signed-off-by: Jonathan Toppins <jtoppins@cumulusnetworks.com> Cc: Andy Gospodarek <gospo@cumulusnetworks.com> Cc: Nikolay Aleksandrov <nikolay@redhat.com> --- drivers/net/bonding/bond_options.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-)