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net: mvneta: Fix an out of bounds check
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In an earlier commit, I added a bounds check to prevent an out of bounds
read and a WARN().  On further discussion and consideration that check
was probably too aggressive.  Instead of returning -EINVAL, a better fix
would be to just prevent the out of bounds read but continue the process.

Background: The value of "pp->rxq_def" is a number between 0-7 by default,
or even higher depending on the value of "rxq_number", which is a module
parameter. If the value is more than the number of available CPUs then
it will trigger the WARN() in cpu_max_bits_warn().

Fixes: e8b4fc1 ("net: mvneta: Prevent out of bounds read in mvneta_config_rss()")
Signed-off-by: Dan Carpenter <error27@gmail.com>
Reviewed-by: Leon Romanovsky <leonro@nvidia.com>
Link: https://lore.kernel.org/r/Y5A7d1E5ccwHTYPf@kadam
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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Dan Carpenter authored and Jakub Kicinski committed Dec 8, 2022
1 parent ed14e59 commit cdd9738
Showing 1 changed file with 1 addition and 4 deletions.
5 changes: 1 addition & 4 deletions drivers/net/ethernet/marvell/mvneta.c
Original file line number Diff line number Diff line change
Expand Up @@ -4271,7 +4271,7 @@ static void mvneta_percpu_elect(struct mvneta_port *pp)
/* Use the cpu associated to the rxq when it is online, in all
* the other cases, use the cpu 0 which can't be offline.
*/
if (cpu_online(pp->rxq_def))
if (pp->rxq_def < nr_cpu_ids && cpu_online(pp->rxq_def))
elected_cpu = pp->rxq_def;

max_cpu = num_present_cpus();
Expand Down Expand Up @@ -4927,9 +4927,6 @@ static int mvneta_config_rss(struct mvneta_port *pp)
napi_disable(&pp->napi);
}

if (pp->indir[0] >= nr_cpu_ids)
return -EINVAL;

pp->rxq_def = pp->indir[0];

/* Update unicast mapping */
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