Re: [PATCH net v2 1/1] xdp: fix xdp_return_frame() kernel BUG throw for page_pool memory model
Hello: This patch was applied to netdev/net.git (refs/heads/master): On Wed, 31 Mar 2021 21:25:03 +0800 you wrote: > xdp_return_frame() may be called outside of NAPI context to return > xdpf back to page_pool. xdp_return_frame() calls __xdp_return() with > napi_direct = false. For page_pool memory model, __xdp_return() calls > xdp_return_frame_no_direct() unconditionally and below false negative > kernel BUG throw happened under preempt-rt build: > > [ 430.450355] BUG: using smp_processor_id() in preemptible [] code: > modprobe/3884 > [ 430.451678] caller is __xdp_return+0x1ff/0x2e0 > [ 430.452111] CPU: 0 PID: 3884 Comm: modprobe Tainted: G U E > 5.12.0-rc2+ #45 > > [...] Here is the summary with links: - [net,v2,1/1] xdp: fix xdp_return_frame() kernel BUG throw for page_pool memory model https://git.kernel.org/netdev/net/c/622d13694b5f You are awesome, thank you! -- Deet-doot-dot, I am a bot. https://korg.docs.kernel.org/patchwork/pwbot.html
Re: [PATCH net v2 1/1] xdp: fix xdp_return_frame() kernel BUG throw for page_pool memory model
On Wed, 31 Mar 2021 21:25:03 +0800 Ong Boon Leong wrote: > xdp_return_frame() may be called outside of NAPI context to return > xdpf back to page_pool. xdp_return_frame() calls __xdp_return() with > napi_direct = false. For page_pool memory model, __xdp_return() calls > xdp_return_frame_no_direct() unconditionally and below false negative > kernel BUG throw happened under preempt-rt build: > > [ 430.450355] BUG: using smp_processor_id() in preemptible [] code: > modprobe/3884 > [ 430.451678] caller is __xdp_return+0x1ff/0x2e0 > [ 430.452111] CPU: 0 PID: 3884 Comm: modprobe Tainted: G U E > 5.12.0-rc2+ #45 > > Changes in v2: > - This patch fixes the issue by making xdp_return_frame_no_direct() is >only called if napi_direct = true, as recommended for better by >Jesper Dangaard Brouer. Thanks! > > Fixes: 2539650fadbf ("xdp: Helpers for disabling napi_direct of > xdp_return_frame") > Signed-off-by: Ong Boon Leong Acked-by: Jesper Dangaard Brouer > --- > net/core/xdp.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/net/core/xdp.c b/net/core/xdp.c > index 05354976c1fc..858276e72c68 100644 > --- a/net/core/xdp.c > +++ b/net/core/xdp.c > @@ -350,7 +350,8 @@ static void __xdp_return(void *data, struct xdp_mem_info > *mem, bool napi_direct, > /* mem->id is valid, checked in xdp_rxq_info_reg_mem_model() */ > xa = rhashtable_lookup(mem_id_ht, >id, mem_id_rht_params); > page = virt_to_head_page(data); > - napi_direct &= !xdp_return_frame_no_direct(); > + if (napi_direct && xdp_return_frame_no_direct()) > + napi_direct = false; > page_pool_put_full_page(xa->page_pool, page, napi_direct); > rcu_read_unlock(); > break; -- Best regards, Jesper Dangaard Brouer MSc.CS, Principal Kernel Engineer at Red Hat LinkedIn: http://www.linkedin.com/in/brouer
[PATCH net v2 1/1] xdp: fix xdp_return_frame() kernel BUG throw for page_pool memory model
xdp_return_frame() may be called outside of NAPI context to return xdpf back to page_pool. xdp_return_frame() calls __xdp_return() with napi_direct = false. For page_pool memory model, __xdp_return() calls xdp_return_frame_no_direct() unconditionally and below false negative kernel BUG throw happened under preempt-rt build: [ 430.450355] BUG: using smp_processor_id() in preemptible [] code: modprobe/3884 [ 430.451678] caller is __xdp_return+0x1ff/0x2e0 [ 430.452111] CPU: 0 PID: 3884 Comm: modprobe Tainted: G U E 5.12.0-rc2+ #45 Changes in v2: - This patch fixes the issue by making xdp_return_frame_no_direct() is only called if napi_direct = true, as recommended for better by Jesper Dangaard Brouer. Thanks! Fixes: 2539650fadbf ("xdp: Helpers for disabling napi_direct of xdp_return_frame") Signed-off-by: Ong Boon Leong --- net/core/xdp.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/net/core/xdp.c b/net/core/xdp.c index 05354976c1fc..858276e72c68 100644 --- a/net/core/xdp.c +++ b/net/core/xdp.c @@ -350,7 +350,8 @@ static void __xdp_return(void *data, struct xdp_mem_info *mem, bool napi_direct, /* mem->id is valid, checked in xdp_rxq_info_reg_mem_model() */ xa = rhashtable_lookup(mem_id_ht, >id, mem_id_rht_params); page = virt_to_head_page(data); - napi_direct &= !xdp_return_frame_no_direct(); + if (napi_direct && xdp_return_frame_no_direct()) + napi_direct = false; page_pool_put_full_page(xa->page_pool, page, napi_direct); rcu_read_unlock(); break; -- 2.25.1