4.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Paul Burton <paul.burton@xxxxxxxxxx> [ Upstream commit d4da0e97baea8768b3d66ccef3967bebd50dfc3b ] If a driver causes DMA cache maintenance with a zero length then we currently BUG and kill the kernel. As this is a scenario that we may well be able to recover from, WARN & return in the condition instead. Signed-off-by: Paul Burton <paul.burton@xxxxxxxx> Acked-by: Florian Fainelli <f.fainelli@xxxxxxxxx> Patchwork: https://patchwork.linux-mips.org/patch/14623/ Cc: Ralf Baechle <ralf@xxxxxxxxxxxxxx> Cc: linux-mips@xxxxxxxxxxxxxx Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- arch/mips/mm/c-r4k.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) --- a/arch/mips/mm/c-r4k.c +++ b/arch/mips/mm/c-r4k.c @@ -835,7 +835,8 @@ static void r4k_flush_icache_user_range( static void r4k_dma_cache_wback_inv(unsigned long addr, unsigned long size) { /* Catch bad driver code */ - BUG_ON(size == 0); + if (WARN_ON(size == 0)) + return; preempt_disable(); if (cpu_has_inclusive_pcaches) { @@ -871,7 +872,8 @@ static void r4k_dma_cache_wback_inv(unsi static void r4k_dma_cache_inv(unsigned long addr, unsigned long size) { /* Catch bad driver code */ - BUG_ON(size == 0); + if (WARN_ON(size == 0)) + return; preempt_disable(); if (cpu_has_inclusive_pcaches) {
