| Message ID | 20210331132503.15926-1-boon.leong.ong@intel.com (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | 622d13694b5f048c01caa7ba548498d9880d4cb0 |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | [net,v2,1/1] xdp: fix xdp_return_frame() kernel BUG throw for page_pool memory model | expand |
| Context | Check | Description |
|---|---|---|
| netdev/cover_letter | success | Link |
| netdev/fixes_present | success | Link |
| netdev/patch_count | success | Link |
| netdev/tree_selection | success | Clearly marked for net |
| netdev/subject_prefix | success | Link |
| netdev/cc_maintainers | warning | 5 maintainers not CCed: yhs@fb.com kpsingh@kernel.org andrii@kernel.org kafai@fb.com songliubraving@fb.com |
| netdev/source_inline | success | Was 0 now: 0 |
| netdev/verify_signedoff | success | Link |
| netdev/module_param | success | Was 0 now: 0 |
| netdev/build_32bit | success | Errors and warnings before: 1 this patch: 1 |
| netdev/kdoc | success | Errors and warnings before: 0 this patch: 0 |
| netdev/verify_fixes | success | Link |
| netdev/checkpatch | success | total: 0 errors, 0 warnings, 0 checks, 9 lines checked |
| netdev/build_allmodconfig_warn | success | Errors and warnings before: 1 this patch: 1 |
| netdev/header_inline | success | Link |
On Wed, 31 Mar 2021 21:25:03 +0800 Ong Boon Leong <boon.leong.ong@intel.com> 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 [00000000] 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 <boon.leong.ong@intel.com> Acked-by: Jesper Dangaard Brouer <brouer@redhat.com> > --- > 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, &mem->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;
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 [00000000] 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
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, &mem->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;
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 [00000000] 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 <boon.leong.ong@intel.com> --- net/core/xdp.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)