[][Backport napi releated bug fixes to openwrt 21.02]
[Description]
Add some napi releated bug fixeds to openwrt 21.02
Please refer to following patches for detail:
https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/commit/net/core/dev.c?id=0315a075f1343966ea2d9a085666a88a69ea6a3d
https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/commit/net/core/dev.c?id=3765996e4f0b8a755cab215a08df744490c76052
https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/commit/net/core/dev.c?id=719c571970109b0d0af24745d31b202affc9365f
Please notice following changed:
+ new &= ~(NAPIF_STATE_THREADED | NAPIF_STATE_PREFER_BUSY_POLL);
/* No "NAPIF_STATE_PREFER_BUSY_POLL" in kernel 5.4 */
- clear_bit(NAPI_STATE_PREFER_BUSY_POLL, &n->state);
Test: Build PASS
[Release-log]
N/A
Change-Id: Icb0d352821fb91108eb08f46f8bda8f1419f7777
Reviewed-on: https://gerrit.mediatek.inc/c/openwrt/feeds/mtk_openwrt_feeds/+/6050622
diff --git a/target/linux/mediatek/patches-5.4/7000-fix-race-inside-napi-enable.patch b/target/linux/mediatek/patches-5.4/7000-fix-race-inside-napi-enable.patch
new file mode 100644
index 0000000..052f40c
--- /dev/null
+++ b/target/linux/mediatek/patches-5.4/7000-fix-race-inside-napi-enable.patch
@@ -0,0 +1,94 @@
+From git@z Thu Jan 1 00:00:00 1970
+Subject: [PATCH v2] napi: fix race inside napi_enable
+From: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
+Date: Sat, 18 Sep 2021 16:52:32 +0800
+Message-Id: <20210918085232.71436-1-xuanzhuo@linux.alibaba.com>
+To: netdev@vger.kernel.org, linyunsheng@huawei.com
+Cc: "David S. Miller" <davem@davemloft.net>, Jakub Kicinski <kuba@kernel.org>, Eric Dumazet <edumazet@google.com>, Daniel Borkmann <daniel@iogearbox.net>, Antoine Tenart <atenart@kernel.org>, Alexander Lobakin <alobakin@pm.me>, Wei Wang <weiwan@google.com>, Taehee Yoo <ap420073@gmail.com>,Björn Töpel <bjorn@kernel.org>, Arnd Bergmann <arnd@arndb.de>, Kumar Kartikeya Dwivedi <memxor@gmail.com>, Neil Horman <nhorman@redhat.com>, Dust Li <dust.li@linux.alibaba.com>
+List-Id: <netdev.vger.kernel.org>
+MIME-Version: 1.0
+Content-Type: text/plain; charset="utf-8"
+Content-Transfer-Encoding: 7bit
+
+The process will cause napi.state to contain NAPI_STATE_SCHED and
+not in the poll_list, which will cause napi_disable() to get stuck.
+
+The prefix "NAPI_STATE_" is removed in the figure below, and
+NAPI_STATE_HASHED is ignored in napi.state.
+
+ CPU0 | CPU1 | napi.state
+===============================================================================
+napi_disable() | | SCHED | NPSVC
+napi_enable() | |
+{ | |
+ smp_mb__before_atomic(); | |
+ clear_bit(SCHED, &n->state); | | NPSVC
+ | napi_schedule_prep() | SCHED | NPSVC
+ | napi_poll() |
+ | napi_complete_done() |
+ | { |
+ | if (n->state & (NPSVC | | (1)
+ | _BUSY_POLL))) |
+ | return false; |
+ | ................ |
+ | } | SCHED | NPSVC
+ | |
+ clear_bit(NPSVC, &n->state); | | SCHED
+} | |
+ | |
+napi_schedule_prep() | | SCHED | MISSED (2)
+
+(1) Here return direct. Because of NAPI_STATE_NPSVC exists.
+(2) NAPI_STATE_SCHED exists. So not add napi.poll_list to sd->poll_list
+
+Since NAPI_STATE_SCHED already exists and napi is not in the
+sd->poll_list queue, NAPI_STATE_SCHED cannot be cleared and will always
+exist.
+
+1. This will cause this queue to no longer receive packets.
+2. If you encounter napi_disable under the protection of rtnl_lock, it
+ will cause the entire rtnl_lock to be locked, affecting the overall
+ system.
+
+This patch uses cmpxchg to implement napi_enable(), which ensures that
+there will be no race due to the separation of clear two bits.
+
+Fixes: 2d8bff12699abc ("netpoll: Close race condition between poll_one_napi and napi_disable")
+Signed-off-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
+Reviewed-by: Dust Li <dust.li@linux.alibaba.com>
+---
+ net/core/dev.c | 16 ++++++++++------
+ 1 file changed, 10 insertions(+), 6 deletions(-)
+
+diff --git a/net/core/dev.c b/net/core/dev.c
+index 74fd402d26dd..7ee9fecd3aff 100644
+--- a/net/core/dev.c
++++ b/net/core/dev.c
+@@ -6923,12 +6923,16 @@ EXPORT_SYMBOL(napi_disable);
+ */
+ void napi_enable(struct napi_struct *n)
+ {
+- BUG_ON(!test_bit(NAPI_STATE_SCHED, &n->state));
+- smp_mb__before_atomic();
+- clear_bit(NAPI_STATE_SCHED, &n->state);
+- clear_bit(NAPI_STATE_NPSVC, &n->state);
+- if (n->dev->threaded && n->thread)
+- set_bit(NAPI_STATE_THREADED, &n->state);
++ unsigned long val, new;
++
++ do {
++ val = READ_ONCE(n->state);
++ BUG_ON(!test_bit(NAPI_STATE_SCHED, &val));
++
++ new = val & ~(NAPIF_STATE_SCHED | NAPIF_STATE_NPSVC);
++ if (n->dev->threaded && n->thread)
++ new |= NAPIF_STATE_THREADED;
++ } while (cmpxchg(&n->state, val, new) != val);
+ }
+ EXPORT_SYMBOL(napi_enable);
+
+
+--
+2.31.0
+
+
diff --git a/target/linux/mediatek/patches-5.4/7001-net-make-napi-disable-symmetric-with-enable.patch b/target/linux/mediatek/patches-5.4/7001-net-make-napi-disable-symmetric-with-enable.patch
new file mode 100644
index 0000000..ac84ffc
--- /dev/null
+++ b/target/linux/mediatek/patches-5.4/7001-net-make-napi-disable-symmetric-with-enable.patch
@@ -0,0 +1,64 @@
+From git@z Thu Jan 1 00:00:00 1970
+Subject: [PATCH v2] net: make napi_disable() symmetric with enable
+From: Jakub Kicinski <kuba@kernel.org>
+Date: Fri, 24 Sep 2021 13:24:53 -0700
+Message-Id: <20210924202453.1051687-1-kuba@kernel.org>
+To: davem@davemloft.net
+Cc: netdev@vger.kernel.org, eric.dumazet@gmail.com, weiwan@google.com, xuanzhuo@linux.alibaba.com, Jakub Kicinski <kuba@kernel.org>
+List-Id: <netdev.vger.kernel.org>
+MIME-Version: 1.0
+Content-Type: text/plain; charset="utf-8"
+Content-Transfer-Encoding: 7bit
+
+Commit 3765996e4f0b ("napi: fix race inside napi_enable") fixed
+an ordering bug in napi_enable() and made the napi_enable() diverge
+from napi_disable(). The state transitions done on disable are
+not symmetric to enable.
+
+There is no known bug in napi_disable() this is just refactoring.
+
+Eric suggests we can also replace msleep(1) with a more opportunistic
+usleep_range().
+
+Signed-off-by: Jakub Kicinski <kuba@kernel.org>
+---
+ net/core/dev.c | 17 ++++++++++++-----
+ 1 file changed, 12 insertions(+), 5 deletions(-)
+
+diff --git a/net/core/dev.c b/net/core/dev.c
+index f24c3a9..f0a556a 100644
+--- a/net/core/dev.c
++++ b/net/core/dev.c
+@@ -6386,18 +6386,25 @@ EXPORT_SYMBOL(netif_napi_add);
+
+ void napi_disable(struct napi_struct *n)
+ {
++ unsigned long val, new;
++
+ might_sleep();
+ set_bit(NAPI_STATE_DISABLE, &n->state);
+
+- while (test_and_set_bit(NAPI_STATE_SCHED, &n->state))
+- msleep(1);
+- while (test_and_set_bit(NAPI_STATE_NPSVC, &n->state))
+- msleep(1);
++ do {
++ val = READ_ONCE(n->state);
++ if (val & (NAPIF_STATE_SCHED | NAPIF_STATE_NPSVC)) {
++ usleep_range(20, 200);
++ continue;
++ }
++
++ new = val | NAPIF_STATE_SCHED | NAPIF_STATE_NPSVC;
++ new &= ~(NAPIF_STATE_THREADED);
++ } while (cmpxchg(&n->state, val, new) != val);
+
+ hrtimer_cancel(&n->timer);
+
+ clear_bit(NAPI_STATE_DISABLE, &n->state);
+- clear_bit(NAPI_STATE_THREADED, &n->state);
+ }
+ EXPORT_SYMBOL(napi_disable);
+
+--
+2.31.1
diff --git a/target/linux/mediatek/patches-5.4/7002-net-fix-premature-exit-from-napi-state-polling-in-napi-disable-v2.patch b/target/linux/mediatek/patches-5.4/7002-net-fix-premature-exit-from-napi-state-polling-in-napi-disable-v2.patch
new file mode 100644
index 0000000..0daf233
--- /dev/null
+++ b/target/linux/mediatek/patches-5.4/7002-net-fix-premature-exit-from-napi-state-polling-in-napi-disable-v2.patch
@@ -0,0 +1,114 @@
+From git@z Thu Jan 1 00:00:00 1970
+Subject: [PATCH v2] net: fix premature exit from NAPI state polling in napi_disable()
+From: Alexander Lobakin <alexandr.lobakin@intel.com>
+Date: Wed, 10 Nov 2021 20:56:05 +0100
+Message-Id: <20211110195605.1304-1-alexandr.lobakin@intel.com>
+To: "David S. Miller" <davem@davemloft.net>, Jakub Kicinski <kuba@kernel.org>
+Cc: Alexander Lobakin <alexandr.lobakin@intel.com>, Jesse Brandeburg <jesse.brandeburg@intel.com>, Maciej Fijalkowski <maciej.fijalkowski@intel.com>, Michal Swiatkowski <michal.swiatkowski@intel.com>, Xuan Zhuo <xuanzhuo@linux.alibaba.com>, Antoine Tenart <atenart@kernel.org>, Eric Dumazet <edumazet@google.com>, Wei Wang <weiwan@google.com>,Björn Töpel <bjorn@kernel.org>, netdev@vger.kernel.org, linux-kernel@vger.kernel.org
+List-Id: <linux-kernel.vger.kernel.org>
+MIME-Version: 1.0
+Content-Type: text/plain; charset="utf-8"
+Content-Transfer-Encoding: 7bit
+
+Commit 719c57197010 ("net: make napi_disable() symmetric with
+enable") accidentally introduced a bug sometimes leading to a kernel
+BUG when bringing an iface up/down under heavy traffic load.
+
+Prior to this commit, napi_disable() was polling n->state until
+none of (NAPIF_STATE_SCHED | NAPIF_STATE_NPSVC) is set and then
+always flip them. Now there's a possibility to get away with the
+NAPIF_STATE_SCHE unset as 'continue' drops us to the cmpxchg()
+call with an unitialized variable, rather than straight to
+another round of the state check.
+
+Error path looks like:
+
+napi_disable():
+unsigned long val, new; /* new is uninitialized */
+
+do {
+ val = READ_ONCE(n->state); /* NAPIF_STATE_NPSVC and/or
+ NAPIF_STATE_SCHED is set */
+ if (val & (NAPIF_STATE_SCHED | NAPIF_STATE_NPSVC)) { /* true */
+ usleep_range(20, 200);
+ continue; /* go straight to the condition check */
+ }
+ new = val | <...>
+} while (cmpxchg(&n->state, val, new) != val); /* state == val, cmpxchg()
+ writes garbage */
+
+napi_enable():
+do {
+ val = READ_ONCE(n->state);
+ BUG_ON(!test_bit(NAPI_STATE_SCHED, &val)); /* 50/50 boom */
+<...>
+
+while the typical BUG splat is like:
+
+[ 172.652461] ------------[ cut here ]------------
+[ 172.652462] kernel BUG at net/core/dev.c:6937!
+[ 172.656914] invalid opcode: 0000 [#1] PREEMPT SMP PTI
+[ 172.661966] CPU: 36 PID: 2829 Comm: xdp_redirect_cp Tainted: G I 5.15.0 #42
+[ 172.670222] Hardware name: Intel Corporation S2600WFT/S2600WFT, BIOS SE5C620.86B.02.01.0014.082620210524 08/26/2021
+[ 172.680646] RIP: 0010:napi_enable+0x5a/0xd0
+[ 172.684832] Code: 07 49 81 cc 00 01 00 00 4c 89 e2 48 89 d8 80 e6 fb f0 48 0f b1 55 10 48 39 c3 74 10 48 8b 5d 10 f6 c7 04 75 3d f6 c3 01 75 b4 <0f> 0b 5b 5d 41 5c c3 65 ff 05 b8 e5 61 53 48 c7 c6 c0 f3 34 ad 48
+[ 172.703578] RSP: 0018:ffffa3c9497477a8 EFLAGS: 00010246
+[ 172.708803] RAX: ffffa3c96615a014 RBX: 0000000000000000 RCX: ffff8a4b575301a0
+< snip >
+[ 172.782403] Call Trace:
+[ 172.784857] <TASK>
+[ 172.786963] ice_up_complete+0x6f/0x210 [ice]
+[ 172.791349] ice_xdp+0x136/0x320 [ice]
+[ 172.795108] ? ice_change_mtu+0x180/0x180 [ice]
+[ 172.799648] dev_xdp_install+0x61/0xe0
+[ 172.803401] dev_xdp_attach+0x1e0/0x550
+[ 172.807240] dev_change_xdp_fd+0x1e6/0x220
+[ 172.811338] do_setlink+0xee8/0x1010
+[ 172.814917] rtnl_setlink+0xe5/0x170
+[ 172.818499] ? bpf_lsm_binder_set_context_mgr+0x10/0x10
+[ 172.823732] ? security_capable+0x36/0x50
+< snip >
+
+Fix this by replacing 'do { } while (cmpxchg())' with an "infinite"
+for-loop with an explicit break.
+
+From v1 [0]:
+ - just use a for-loop to simplify both the fix and the existing
+ code (Eric).
+
+[0] https://lore.kernel.org/netdev/20211110191126.1214-1-alexandr.lobakin@intel.com
+
+Fixes: 719c57197010 ("net: make napi_disable() symmetric with enable")
+Suggested-by: Eric Dumazet <edumazet@google.com> # for-loop
+Signed-off-by: Alexander Lobakin <alexandr.lobakin@intel.com>
+Reviewed-by: Jesse Brandeburg <jesse.brandeburg@intel.com>
+Reviewed-by: Eric Dumazet <edumazet@google.com>
+---
+ net/core/dev.c | 7 +++++--
+ 1 file changed, 5 insertions(+), 2 deletions(-)
+
+diff --git a/net/core/dev.c b/net/core/dev.c
+index c8f7c15..fe2c856 100644
+--- a/net/core/dev.c
++++ b/net/core/dev.c
+@@ -6391,7 +6391,7 @@ void napi_disable(struct napi_struct *n)
+ might_sleep();
+ set_bit(NAPI_STATE_DISABLE, &n->state);
+
+- do {
++ for ( ; ; ) {
+ val = READ_ONCE(n->state);
+ if (val & (NAPIF_STATE_SCHED | NAPIF_STATE_NPSVC)) {
+ usleep_range(20, 200);
+@@ -6400,7 +6400,10 @@ void napi_disable(struct napi_struct *n)
+
+ new = val | NAPIF_STATE_SCHED | NAPIF_STATE_NPSVC;
+ new &= ~(NAPIF_STATE_THREADED);
+- } while (cmpxchg(&n->state, val, new) != val);
++
++ if (cmpxchg(&n->state, val, new) == val)
++ break;
++ }
+
+ hrtimer_cancel(&n->timer);
+