Messages in this thread | | | Date | Tue, 29 Nov 2022 09:33:45 -0700 | Subject | Re: [PATCH net] net: Add a gfp_t parameter in ip_fib_metrics_init to support atomic context | From | David Ahern <> |
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On 11/28/22 10:53 PM, Duoming Zhou wrote: > The ip_fib_metrics_init() do not support atomic context, because it > calls "kzalloc(..., GFP_KERNEL)". When ip_fib_metrics_init() is used > in atomic context, the sleep-in-atomic-context bug will happen.
Did you actually hit this sleep-in-atomic-context bug or is it theory based on code analysis?
> > For example, the neigh_proxy_process() is a timer handler that is > used to process the proxy request that is timeout. But it could call > ip_fib_metrics_init(). As a result, the can_block flag in ipv6_add_addr() > and the gfp_flags in addrconf_f6i_alloc() and ip6_route_info_create() > are useless. The process is shown below. > > (atomic context) > neigh_proxy_process() > pndisc_redo() > ndisc_recv_ns() > addrconf_dad_failure() > ipv6_add_addr(..., bool can_block) > addrconf_f6i_alloc(..., gfp_t gfp_flags)
cfg has fc_mx == NULL.
> ip6_route_info_create(..., gfp_t gfp_flags)
rt->fib6_metrics = ip_fib_metrics_init(net, cfg->fc_mx, cfg->fc_mx_len, extack);
> ip_fib_metrics_init()
if (!fc_mx) return (struct dst_metrics *)&dst_default_metrics;
> kzalloc(..., GFP_KERNEL) //may sleep >
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