From: Kaige Li <lika...@loongson.cn> Date: Tue, 23 Jun 2020 16:13:09 +0800
> The kernel module may sleep with holding a spinlock. > > The function call paths (from bottom to top) are: > > [FUNC] zalloc_cpumask_var(GFP_KERNEL) > drivers/net/ethernet/cisco/enic/enic_main.c, 125: zalloc_cpumask_var in > enic_init_affinity_hint > drivers/net/ethernet/cisco/enic/enic_main.c, 1918: enic_init_affinity_hint in > enic_open > drivers/net/ethernet/cisco/enic/enic_main.c, 2348: enic_open in enic_reset > drivers/net/ethernet/cisco/enic/enic_main.c, 2341: spin_lock in enic_reset > > To fix this bug, GFP_KERNEL is replaced with GFP_ATOMIC. > > Signed-off-by: Kaige Li <lika...@loongson.cn> Just grepping around for GFP_KERNEL usage in atomic contexts I guess is fine. But you really have to look at the bigger picture. Calling a NIC driver open function from a context holding a spinlock is very much the real problem, so many operations have to sleep and in face that ->ndo_open() method is defined as being allowed to sleep and that's why the core networking never invokes it with spinlocks held.
