diff mbox series

[net-next] inet: ipmr: fix data-races

Message ID 20250113171509.3491883-1-edumazet@google.com (mailing list archive)
State Superseded
Delegated to: Netdev Maintainers
Headers show
Series [net-next] inet: ipmr: fix data-races | expand

Checks

Context Check Description
netdev/series_format success Single patches do not need cover letters
netdev/tree_selection success Clearly marked for net-next
netdev/ynl success Generated files up to date; no warnings/errors; no diff in generated;
netdev/fixes_present success Fixes tag not required for -next series
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit fail Errors and warnings before: 1 this patch: 12
netdev/build_tools success Errors and warnings before: 0 (+1) this patch: 0 (+1)
netdev/cc_maintainers success CCed 6 of 6 maintainers
netdev/build_clang fail Errors and warnings before: 34 this patch: 36
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/deprecated_api success None detected
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success Fixes tag looks correct
netdev/build_allmodconfig_warn fail Errors and warnings before: 20 this patch: 31
netdev/checkpatch warning WARNING: line length of 83 exceeds 80 columns WARNING: line length of 84 exceeds 80 columns
netdev/build_clang_rust success No Rust files in patch. Skipping build
netdev/kdoc success Errors and warnings before: 14 this patch: 14
netdev/source_inline success Was 0 now: 0

Commit Message

Eric Dumazet Jan. 13, 2025, 5:15 p.m. UTC 
Following fields of 'struct mr_mfc' can be updated
concurrently (no lock protection) from ip_mr_forward()
and ip6_mr_forward()

- bytes
- pkt
- wrong_if
- lastuse

They also can be read from other functions.

Convert bytes, pkt and wrong_if to atomic_long_t,
and use READ_ONCE()/WRITE_ONCE() for lastuse.

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Eric Dumazet <edumazet@google.com>
---
 include/linux/mroute_base.h |  6 +++---
 net/ipv4/ipmr.c             | 28 ++++++++++++++--------------
 net/ipv4/ipmr_base.c        |  6 +++---
 net/ipv6/ip6mr.c            | 28 ++++++++++++++--------------
 4 files changed, 34 insertions(+), 34 deletions(-)

Comments

David Ahern Jan. 14, 2025, 12:35 a.m. UTC | #1 
On 1/13/25 10:15 AM, Eric Dumazet wrote:
> Following fields of 'struct mr_mfc' can be updated
> concurrently (no lock protection) from ip_mr_forward()
> and ip6_mr_forward()
> 
> - bytes
> - pkt
> - wrong_if
> - lastuse
> 
> They also can be read from other functions.
> 
> Convert bytes, pkt and wrong_if to atomic_long_t,
> and use READ_ONCE()/WRITE_ONCE() for lastuse.
> 
> Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
> Signed-off-by: Eric Dumazet <edumazet@google.com>
> ---
>  include/linux/mroute_base.h |  6 +++---
>  net/ipv4/ipmr.c             | 28 ++++++++++++++--------------
>  net/ipv4/ipmr_base.c        |  6 +++---
>  net/ipv6/ip6mr.c            | 28 ++++++++++++++--------------
>  4 files changed, 34 insertions(+), 34 deletions(-)
> 

Reviewed-by: David Ahern <dsahern@kernel.org>
Jakub Kicinski Jan. 14, 2025, 9:36 p.m. UTC | #2 
On Mon, 13 Jan 2025 17:15:09 +0000 Eric Dumazet wrote:
> Following fields of 'struct mr_mfc' can be updated
> concurrently (no lock protection) from ip_mr_forward()
> and ip6_mr_forward()
> 
> - bytes
> - pkt
> - wrong_if
> - lastuse
> 
> They also can be read from other functions.
> 
> Convert bytes, pkt and wrong_if to atomic_long_t,
> and use READ_ONCE()/WRITE_ONCE() for lastuse.

Drivers poke into this:

drivers/net/ethernet/mellanox/mlxsw/spectrum_mr.c:1006:43: error: invalid operands to binary != (have ‘atomic_long_t’ {aka ‘atomic64_t’} and ‘u64’ {aka ‘long long unsigned int’})
+ 1006 |         if (mr_route->mfc->mfc_un.res.pkt != packets)
+      |             ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ^~
+      |                                      |
+      |                                      atomic_long_t {aka atomic64_t}
Eric Dumazet Jan. 14, 2025, 9:59 p.m. UTC | #3 
On Tue, Jan 14, 2025 at 10:36 PM Jakub Kicinski <kuba@kernel.org> wrote:
>
> On Mon, 13 Jan 2025 17:15:09 +0000 Eric Dumazet wrote:
> > Following fields of 'struct mr_mfc' can be updated
> > concurrently (no lock protection) from ip_mr_forward()
> > and ip6_mr_forward()
> >
> > - bytes
> > - pkt
> > - wrong_if
> > - lastuse
> >
> > They also can be read from other functions.
> >
> > Convert bytes, pkt and wrong_if to atomic_long_t,
> > and use READ_ONCE()/WRITE_ONCE() for lastuse.
>
> Drivers poke into this:
>
> drivers/net/ethernet/mellanox/mlxsw/spectrum_mr.c:1006:43: error: invalid operands to binary != (have ‘atomic_long_t’ {aka ‘atomic64_t’} and ‘u64’ {aka ‘long long unsigned int’})
> + 1006 |         if (mr_route->mfc->mfc_un.res.pkt != packets)
> +      |             ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ^~
> +      |                                      |
> +      |                                      atomic_long_t {aka atomic64_t}

Oops, oh well, thanks, I will send a V2.
diff mbox series

Patch

diff --git a/include/linux/mroute_base.h b/include/linux/mroute_base.h
index 9dd4bf1572553ffbf41bade97393fac091797a8d..58a2401e4b551bad0eadb9c5d4c341ddad48b39b 100644
--- a/include/linux/mroute_base.h
+++ b/include/linux/mroute_base.h
@@ -146,9 +146,9 @@  struct mr_mfc {
 			unsigned long last_assert;
 			int minvif;
 			int maxvif;
-			unsigned long bytes;
-			unsigned long pkt;
-			unsigned long wrong_if;
+			atomic_long_t bytes;
+			atomic_long_t pkt;
+			atomic_long_t wrong_if;
 			unsigned long lastuse;
 			unsigned char ttls[MAXVIFS];
 			refcount_t refcount;
diff --git a/net/ipv4/ipmr.c b/net/ipv4/ipmr.c
index 99d8faa508e5325c653c920855a52f24b661618c..21ae7594a8525a0df01ce01b801d0075dada0959 100644
--- a/net/ipv4/ipmr.c
+++ b/net/ipv4/ipmr.c
@@ -831,7 +831,7 @@  static void ipmr_update_thresholds(struct mr_table *mrt, struct mr_mfc *cache,
 				cache->mfc_un.res.maxvif = vifi + 1;
 		}
 	}
-	cache->mfc_un.res.lastuse = jiffies;
+	WRITE_ONCE(cache->mfc_un.res.lastuse, jiffies);
 }
 
 static int vif_add(struct net *net, struct mr_table *mrt,
@@ -1681,9 +1681,9 @@  int ipmr_ioctl(struct sock *sk, int cmd, void *arg)
 		rcu_read_lock();
 		c = ipmr_cache_find(mrt, sr->src.s_addr, sr->grp.s_addr);
 		if (c) {
-			sr->pktcnt = c->_c.mfc_un.res.pkt;
-			sr->bytecnt = c->_c.mfc_un.res.bytes;
-			sr->wrong_if = c->_c.mfc_un.res.wrong_if;
+			sr->pktcnt = atomic_long_read(&c->_c.mfc_un.res.pkt);
+			sr->bytecnt = atomic_long_read(&c->_c.mfc_un.res.bytes);
+			sr->wrong_if = atomic_long_read(&c->_c.mfc_un.res.wrong_if);
 			rcu_read_unlock();
 			return 0;
 		}
@@ -1753,9 +1753,9 @@  int ipmr_compat_ioctl(struct sock *sk, unsigned int cmd, void __user *arg)
 		rcu_read_lock();
 		c = ipmr_cache_find(mrt, sr.src.s_addr, sr.grp.s_addr);
 		if (c) {
-			sr.pktcnt = c->_c.mfc_un.res.pkt;
-			sr.bytecnt = c->_c.mfc_un.res.bytes;
-			sr.wrong_if = c->_c.mfc_un.res.wrong_if;
+			sr.pktcnt = atomic_long_read(&c->_c.mfc_un.res.pkt);
+			sr.bytecnt = atomic_long_read(&c->_c.mfc_un.res.bytes);
+			sr.wrong_if = atomic_long_read(&c->_c.mfc_un.res.wrong_if);
 			rcu_read_unlock();
 
 			if (copy_to_user(arg, &sr, sizeof(sr)))
@@ -1988,9 +1988,9 @@  static void ip_mr_forward(struct net *net, struct mr_table *mrt,
 	int vif, ct;
 
 	vif = c->_c.mfc_parent;
-	c->_c.mfc_un.res.pkt++;
-	c->_c.mfc_un.res.bytes += skb->len;
-	c->_c.mfc_un.res.lastuse = jiffies;
+	atomic_long_inc(&c->_c.mfc_un.res.pkt);
+	atomic_long_add(skb->len, &c->_c.mfc_un.res.bytes);
+	WRITE_ONCE(c->_c.mfc_un.res.lastuse, jiffies);
 
 	if (c->mfc_origin == htonl(INADDR_ANY) && true_vifi >= 0) {
 		struct mfc_cache *cache_proxy;
@@ -2021,7 +2021,7 @@  static void ip_mr_forward(struct net *net, struct mr_table *mrt,
 			goto dont_forward;
 		}
 
-		c->_c.mfc_un.res.wrong_if++;
+		atomic_long_inc(&c->_c.mfc_un.res.wrong_if);
 
 		if (true_vifi >= 0 && mrt->mroute_do_assert &&
 		    /* pimsm uses asserts, when switching from RPT to SPT,
@@ -3029,9 +3029,9 @@  static int ipmr_mfc_seq_show(struct seq_file *seq, void *v)
 
 		if (it->cache != &mrt->mfc_unres_queue) {
 			seq_printf(seq, " %8lu %8lu %8lu",
-				   mfc->_c.mfc_un.res.pkt,
-				   mfc->_c.mfc_un.res.bytes,
-				   mfc->_c.mfc_un.res.wrong_if);
+				   atomic_long_read(&mfc->_c.mfc_un.res.pkt),
+				   atomic_long_read(&mfc->_c.mfc_un.res.bytes),
+				   atomic_long_read(&mfc->_c.mfc_un.res.wrong_if));
 			for (n = mfc->_c.mfc_un.res.minvif;
 			     n < mfc->_c.mfc_un.res.maxvif; n++) {
 				if (VIF_EXISTS(mrt, n) &&
diff --git a/net/ipv4/ipmr_base.c b/net/ipv4/ipmr_base.c
index f0af12a2f70bcdf5ba54321bf7ebebe798318abb..03b6eee407a24117612d2254c5eb72e78f39c196 100644
--- a/net/ipv4/ipmr_base.c
+++ b/net/ipv4/ipmr_base.c
@@ -263,9 +263,9 @@  int mr_fill_mroute(struct mr_table *mrt, struct sk_buff *skb,
 	lastuse = READ_ONCE(c->mfc_un.res.lastuse);
 	lastuse = time_after_eq(jiffies, lastuse) ? jiffies - lastuse : 0;
 
-	mfcs.mfcs_packets = c->mfc_un.res.pkt;
-	mfcs.mfcs_bytes = c->mfc_un.res.bytes;
-	mfcs.mfcs_wrong_if = c->mfc_un.res.wrong_if;
+	mfcs.mfcs_packets = atomic_long_read(&c->mfc_un.res.pkt);
+	mfcs.mfcs_bytes = atomic_long_read(&c->mfc_un.res.bytes);
+	mfcs.mfcs_wrong_if = atomic_long_read(&c->mfc_un.res.wrong_if);
 	if (nla_put_64bit(skb, RTA_MFC_STATS, sizeof(mfcs), &mfcs, RTA_PAD) ||
 	    nla_put_u64_64bit(skb, RTA_EXPIRES, jiffies_to_clock_t(lastuse),
 			      RTA_PAD))
diff --git a/net/ipv6/ip6mr.c b/net/ipv6/ip6mr.c
index 578ff1336afeff7a9f468d54c8fc47fddcaedbbb..535e9f72514c06ad655e46d3200c14298f584d99 100644
--- a/net/ipv6/ip6mr.c
+++ b/net/ipv6/ip6mr.c
@@ -520,9 +520,9 @@  static int ipmr_mfc_seq_show(struct seq_file *seq, void *v)
 
 		if (it->cache != &mrt->mfc_unres_queue) {
 			seq_printf(seq, " %8lu %8lu %8lu",
-				   mfc->_c.mfc_un.res.pkt,
-				   mfc->_c.mfc_un.res.bytes,
-				   mfc->_c.mfc_un.res.wrong_if);
+				   atomic_long_read(&mfc->_c.mfc_un.res.pkt),
+				   atomic_long_read(&mfc->_c.mfc_un.res.bytes),
+				   atomic_long_read(&mfc->_c.mfc_un.res.wrong_if));
 			for (n = mfc->_c.mfc_un.res.minvif;
 			     n < mfc->_c.mfc_un.res.maxvif; n++) {
 				if (VIF_EXISTS(mrt, n) &&
@@ -884,7 +884,7 @@  static void ip6mr_update_thresholds(struct mr_table *mrt,
 				cache->mfc_un.res.maxvif = vifi + 1;
 		}
 	}
-	cache->mfc_un.res.lastuse = jiffies;
+	WRITE_ONCE(cache->mfc_un.res.lastuse, jiffies);
 }
 
 static int mif6_add(struct net *net, struct mr_table *mrt,
@@ -1945,9 +1945,9 @@  int ip6mr_ioctl(struct sock *sk, int cmd, void *arg)
 		c = ip6mr_cache_find(mrt, &sr->src.sin6_addr,
 				     &sr->grp.sin6_addr);
 		if (c) {
-			sr->pktcnt = c->_c.mfc_un.res.pkt;
-			sr->bytecnt = c->_c.mfc_un.res.bytes;
-			sr->wrong_if = c->_c.mfc_un.res.wrong_if;
+			sr->pktcnt = atomic_long_read(&c->_c.mfc_un.res.pkt);
+			sr->bytecnt = atomic_long_read(&c->_c.mfc_un.res.bytes);
+			sr->wrong_if = atomic_long_read(&c->_c.mfc_un.res.wrong_if);
 			rcu_read_unlock();
 			return 0;
 		}
@@ -2017,9 +2017,9 @@  int ip6mr_compat_ioctl(struct sock *sk, unsigned int cmd, void __user *arg)
 		rcu_read_lock();
 		c = ip6mr_cache_find(mrt, &sr.src.sin6_addr, &sr.grp.sin6_addr);
 		if (c) {
-			sr.pktcnt = c->_c.mfc_un.res.pkt;
-			sr.bytecnt = c->_c.mfc_un.res.bytes;
-			sr.wrong_if = c->_c.mfc_un.res.wrong_if;
+			sr.pktcnt = atomic_long_read(&c->_c.mfc_un.res.pkt);
+			sr.bytecnt = atomic_long_read(&c->_c.mfc_un.res.bytes);
+			sr.wrong_if = atomic_long_read(&c->_c.mfc_un.res.wrong_if);
 			rcu_read_unlock();
 
 			if (copy_to_user(arg, &sr, sizeof(sr)))
@@ -2142,9 +2142,9 @@  static void ip6_mr_forward(struct net *net, struct mr_table *mrt,
 	int true_vifi = ip6mr_find_vif(mrt, dev);
 
 	vif = c->_c.mfc_parent;
-	c->_c.mfc_un.res.pkt++;
-	c->_c.mfc_un.res.bytes += skb->len;
-	c->_c.mfc_un.res.lastuse = jiffies;
+	atomic_long_inc(&c->_c.mfc_un.res.pkt);
+	atomic_long_add(skb->len, &c->_c.mfc_un.res.bytes);
+	WRITE_ONCE(c->_c.mfc_un.res.lastuse, jiffies);
 
 	if (ipv6_addr_any(&c->mf6c_origin) && true_vifi >= 0) {
 		struct mfc6_cache *cache_proxy;
@@ -2162,7 +2162,7 @@  static void ip6_mr_forward(struct net *net, struct mr_table *mrt,
 	 * Wrong interface: drop packet and (maybe) send PIM assert.
 	 */
 	if (rcu_access_pointer(mrt->vif_table[vif].dev) != dev) {
-		c->_c.mfc_un.res.wrong_if++;
+		atomic_long_inc(&c->_c.mfc_un.res.wrong_if);
 
 		if (true_vifi >= 0 && mrt->mroute_do_assert &&
 		    /* pimsm uses asserts, when switching from RPT to SPT,