* [PATCH net 1/2] mptcp: fix fwd memory accounting on coalesce
@ 2022-09-06 18:04 Matthieu Baerts
2022-09-06 18:04 ` [PATCH net 2/2] Documentation: mptcp: fix pm_type formatting Matthieu Baerts
` (2 more replies)
0 siblings, 3 replies; 4+ messages in thread
From: Matthieu Baerts @ 2022-09-06 18:04 UTC (permalink / raw)
To: Mat Martineau, Matthieu Baerts, David S. Miller, Eric Dumazet,
Jakub Kicinski, Paolo Abeni
Cc: kernel test robot, netdev, mptcp, linux-kernel
From: Paolo Abeni <pabeni@redhat.com>
The intel bot reported a memory accounting related splat:
[ 240.473094] ------------[ cut here ]------------
[ 240.478507] page_counter underflow: -4294828518 nr_pages=4294967290
[ 240.485500] WARNING: CPU: 2 PID: 14986 at mm/page_counter.c:56 page_counter_cancel+0x96/0xc0
[ 240.570849] CPU: 2 PID: 14986 Comm: mptcp_connect Tainted: G S 5.19.0-rc4-00739-gd24141fe7b48 #1
[ 240.581637] Hardware name: HP HP Z240 SFF Workstation/802E, BIOS N51 Ver. 01.63 10/05/2017
[ 240.590600] RIP: 0010:page_counter_cancel+0x96/0xc0
[ 240.596179] Code: 00 00 00 45 31 c0 48 89 ef 5d 4c 89 c6 41 5c e9 40 fd ff ff 4c 89 e2 48 c7 c7 20 73 39 84 c6 05 d5 b1 52 04 01 e8 e7 95 f3
01 <0f> 0b eb a9 48 89 ef e8 1e 25 fc ff eb c3 66 66 2e 0f 1f 84 00 00
[ 240.615639] RSP: 0018:ffffc9000496f7c8 EFLAGS: 00010082
[ 240.621569] RAX: 0000000000000000 RBX: ffff88819c9c0120 RCX: 0000000000000000
[ 240.629404] RDX: 0000000000000027 RSI: 0000000000000004 RDI: fffff5200092deeb
[ 240.637239] RBP: ffff88819c9c0120 R08: 0000000000000001 R09: ffff888366527a2b
[ 240.645069] R10: ffffed106cca4f45 R11: 0000000000000001 R12: 00000000fffffffa
[ 240.652903] R13: ffff888366536118 R14: 00000000fffffffa R15: ffff88819c9c0000
[ 240.660738] FS: 00007f3786e72540(0000) GS:ffff888366500000(0000) knlGS:0000000000000000
[ 240.669529] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 240.675974] CR2: 00007f966b346000 CR3: 0000000168cea002 CR4: 00000000003706e0
[ 240.683807] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[ 240.691641] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[ 240.699468] Call Trace:
[ 240.702613] <TASK>
[ 240.705413] page_counter_uncharge+0x29/0x80
[ 240.710389] drain_stock+0xd0/0x180
[ 240.714585] refill_stock+0x278/0x580
[ 240.718951] __sk_mem_reduce_allocated+0x222/0x5c0
[ 240.729248] __mptcp_update_rmem+0x235/0x2c0
[ 240.734228] __mptcp_move_skbs+0x194/0x6c0
[ 240.749764] mptcp_recvmsg+0xdfa/0x1340
[ 240.763153] inet_recvmsg+0x37f/0x500
[ 240.782109] sock_read_iter+0x24a/0x380
[ 240.805353] new_sync_read+0x420/0x540
[ 240.838552] vfs_read+0x37f/0x4c0
[ 240.842582] ksys_read+0x170/0x200
[ 240.864039] do_syscall_64+0x5c/0x80
[ 240.872770] entry_SYSCALL_64_after_hwframe+0x46/0xb0
[ 240.878526] RIP: 0033:0x7f3786d9ae8e
[ 240.882805] Code: c0 e9 b6 fe ff ff 50 48 8d 3d 6e 18 0a 00 e8 89 e8 01 00 66 0f 1f 84 00 00 00 00 00 64 8b 04 25 18 00 00 00 85 c0 75 14 0f 05 <48> 3d 00 f0 ff ff 77 5a c3 66 0f 1f 84 00 00 00 00 00 48 83 ec 28
[ 240.902259] RSP: 002b:00007fff7be81e08 EFLAGS: 00000246 ORIG_RAX: 0000000000000000
[ 240.910533] RAX: ffffffffffffffda RBX: 0000000000002000 RCX: 00007f3786d9ae8e
[ 240.918368] RDX: 0000000000002000 RSI: 00007fff7be87ec0 RDI: 0000000000000005
[ 240.926206] RBP: 0000000000000005 R08: 00007f3786e6a230 R09: 00007f3786e6a240
[ 240.934046] R10: fffffffffffff288 R11: 0000000000000246 R12: 0000000000002000
[ 240.941884] R13: 00007fff7be87ec0 R14: 00007fff7be87ec0 R15: 0000000000002000
[ 240.949741] </TASK>
[ 240.952632] irq event stamp: 27367
[ 240.956735] hardirqs last enabled at (27366): [<ffffffff81ba50ea>] mem_cgroup_uncharge_skmem+0x6a/0x80
[ 240.966848] hardirqs last disabled at (27367): [<ffffffff81b8fd42>] refill_stock+0x282/0x580
[ 240.976017] softirqs last enabled at (27360): [<ffffffff83a4d8ef>] mptcp_recvmsg+0xaf/0x1340
[ 240.985273] softirqs last disabled at (27364): [<ffffffff83a4d30c>] __mptcp_move_skbs+0x18c/0x6c0
[ 240.994872] ---[ end trace 0000000000000000 ]---
After commit d24141fe7b48 ("mptcp: drop SK_RECLAIM_* macros"),
if rmem_fwd_alloc become negative, mptcp_rmem_uncharge() can
try to reclaim a negative amount of pages, since the expression:
reclaimable >= PAGE_SIZE
will evaluate to true for any negative value of the int
'reclaimable': 'PAGE_SIZE' is an unsigned long and
the negative integer will be promoted to a (very large)
unsigned long value.
Still after the mentioned commit, kfree_skb_partial()
in mptcp_try_coalesce() will reclaim most of just released fwd
memory, so that following charging of the skb delta size will
lead to negative fwd memory values.
At that point a racing recvmsg() can trigger the splat.
Address the issue switching the order of the memory accounting
operations. The fwd memory can still transiently reach negative
values, but that will happen in an atomic scope and no code
path could touch/use such value.
Reported-by: kernel test robot <oliver.sang@intel.com>
Fixes: d24141fe7b48 ("mptcp: drop SK_RECLAIM_* macros")
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: Matthieu Baerts <matthieu.baerts@tessares.net>
---
net/mptcp/protocol.c | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)
diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c
index d398f3810662..969b33a9dd64 100644
--- a/net/mptcp/protocol.c
+++ b/net/mptcp/protocol.c
@@ -150,9 +150,15 @@ static bool mptcp_try_coalesce(struct sock *sk, struct sk_buff *to,
MPTCP_SKB_CB(from)->map_seq, MPTCP_SKB_CB(to)->map_seq,
to->len, MPTCP_SKB_CB(from)->end_seq);
MPTCP_SKB_CB(to)->end_seq = MPTCP_SKB_CB(from)->end_seq;
- kfree_skb_partial(from, fragstolen);
+
+ /* note the fwd memory can reach a negative value after accounting
+ * for the delta, but the later skb free will restore a non
+ * negative one
+ */
atomic_add(delta, &sk->sk_rmem_alloc);
mptcp_rmem_charge(sk, delta);
+ kfree_skb_partial(from, fragstolen);
+
return true;
}
--
2.37.2
^ permalink raw reply related [flat|nested] 4+ messages in thread
* [PATCH net 2/2] Documentation: mptcp: fix pm_type formatting
2022-09-06 18:04 [PATCH net 1/2] mptcp: fix fwd memory accounting on coalesce Matthieu Baerts
@ 2022-09-06 18:04 ` Matthieu Baerts
2022-09-06 18:04 ` [PATCH net 0/2] mptcp: fix fwd memory accounting and doc format Matthieu Baerts
2022-09-13 8:30 ` [PATCH net 1/2] mptcp: fix fwd memory accounting on coalesce patchwork-bot+netdevbpf
2 siblings, 0 replies; 4+ messages in thread
From: Matthieu Baerts @ 2022-09-06 18:04 UTC (permalink / raw)
To: Mat Martineau, Matthieu Baerts, David S. Miller, Eric Dumazet,
Jakub Kicinski, Paolo Abeni, Jonathan Corbet
Cc: netdev, mptcp, linux-doc, linux-kernel
When looking at the rendered HTML version, we can see 'pm_type' is not
displayed with a bold font:
https://docs.kernel.org/5.19/networking/mptcp-sysctl.html
The empty line under 'pm_type' is then removed to have the same style as
the others.
Fixes: 6bb63ccc25d4 ("mptcp: Add a per-namespace sysctl to set the default path manager type")
Signed-off-by: Matthieu Baerts <matthieu.baerts@tessares.net>
---
Documentation/networking/mptcp-sysctl.rst | 1 -
1 file changed, 1 deletion(-)
diff --git a/Documentation/networking/mptcp-sysctl.rst b/Documentation/networking/mptcp-sysctl.rst
index e263dfcc4b40..213510698014 100644
--- a/Documentation/networking/mptcp-sysctl.rst
+++ b/Documentation/networking/mptcp-sysctl.rst
@@ -47,7 +47,6 @@ allow_join_initial_addr_port - BOOLEAN
Default: 1
pm_type - INTEGER
-
Set the default path manager type to use for each new MPTCP
socket. In-kernel path management will control subflow
connections and address advertisements according to
--
2.37.2
^ permalink raw reply related [flat|nested] 4+ messages in thread
* [PATCH net 0/2] mptcp: fix fwd memory accounting and doc format
2022-09-06 18:04 [PATCH net 1/2] mptcp: fix fwd memory accounting on coalesce Matthieu Baerts
2022-09-06 18:04 ` [PATCH net 2/2] Documentation: mptcp: fix pm_type formatting Matthieu Baerts
@ 2022-09-06 18:04 ` Matthieu Baerts
2022-09-13 8:30 ` [PATCH net 1/2] mptcp: fix fwd memory accounting on coalesce patchwork-bot+netdevbpf
2 siblings, 0 replies; 4+ messages in thread
From: Matthieu Baerts @ 2022-09-06 18:04 UTC (permalink / raw)
To: David S. Miller, Eric Dumazet, Jakub Kicinski, Jonathan Corbet,
Mat Martineau, Matthieu Baerts, Paolo Abeni
Cc: linux-doc, linux-kernel, mptcp, netdev
Patch 1 fixes a memory accounting related splat reported by Intel's bot. It
fixes a regression introduced in this cycle (v6.0-rc1).
Patch 2 fixes a formatting issue in the documentation. The issue had been
introduced in the previous version (v5.19).
Matthieu Baerts (1):
Documentation: mptcp: fix pm_type formatting
Paolo Abeni (1):
mptcp: fix fwd memory accounting on coalesce
Documentation/networking/mptcp-sysctl.rst | 1 -
net/mptcp/protocol.c | 8 +++++++-
2 files changed, 7 insertions(+), 2 deletions(-)
base-commit: e1091e226a2bab4ded1fe26efba2aee1aab06450
--
2.37.2
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH net 1/2] mptcp: fix fwd memory accounting on coalesce
2022-09-06 18:04 [PATCH net 1/2] mptcp: fix fwd memory accounting on coalesce Matthieu Baerts
2022-09-06 18:04 ` [PATCH net 2/2] Documentation: mptcp: fix pm_type formatting Matthieu Baerts
2022-09-06 18:04 ` [PATCH net 0/2] mptcp: fix fwd memory accounting and doc format Matthieu Baerts
@ 2022-09-13 8:30 ` patchwork-bot+netdevbpf
2 siblings, 0 replies; 4+ messages in thread
From: patchwork-bot+netdevbpf @ 2022-09-13 8:30 UTC (permalink / raw)
To: Matthieu Baerts
Cc: mathew.j.martineau, davem, edumazet, kuba, pabeni, oliver.sang,
netdev, mptcp, linux-kernel
Hello:
This series was applied to netdev/net.git (master)
by Paolo Abeni <pabeni@redhat.com>:
On Tue, 6 Sep 2022 20:04:01 +0200 you wrote:
> From: Paolo Abeni <pabeni@redhat.com>
>
> The intel bot reported a memory accounting related splat:
>
> [ 240.473094] ------------[ cut here ]------------
> [ 240.478507] page_counter underflow: -4294828518 nr_pages=4294967290
> [ 240.485500] WARNING: CPU: 2 PID: 14986 at mm/page_counter.c:56 page_counter_cancel+0x96/0xc0
> [ 240.570849] CPU: 2 PID: 14986 Comm: mptcp_connect Tainted: G S 5.19.0-rc4-00739-gd24141fe7b48 #1
> [ 240.581637] Hardware name: HP HP Z240 SFF Workstation/802E, BIOS N51 Ver. 01.63 10/05/2017
> [ 240.590600] RIP: 0010:page_counter_cancel+0x96/0xc0
> [ 240.596179] Code: 00 00 00 45 31 c0 48 89 ef 5d 4c 89 c6 41 5c e9 40 fd ff ff 4c 89 e2 48 c7 c7 20 73 39 84 c6 05 d5 b1 52 04 01 e8 e7 95 f3
> 01 <0f> 0b eb a9 48 89 ef e8 1e 25 fc ff eb c3 66 66 2e 0f 1f 84 00 00
> [ 240.615639] RSP: 0018:ffffc9000496f7c8 EFLAGS: 00010082
> [ 240.621569] RAX: 0000000000000000 RBX: ffff88819c9c0120 RCX: 0000000000000000
> [ 240.629404] RDX: 0000000000000027 RSI: 0000000000000004 RDI: fffff5200092deeb
> [ 240.637239] RBP: ffff88819c9c0120 R08: 0000000000000001 R09: ffff888366527a2b
> [ 240.645069] R10: ffffed106cca4f45 R11: 0000000000000001 R12: 00000000fffffffa
> [ 240.652903] R13: ffff888366536118 R14: 00000000fffffffa R15: ffff88819c9c0000
> [ 240.660738] FS: 00007f3786e72540(0000) GS:ffff888366500000(0000) knlGS:0000000000000000
> [ 240.669529] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> [ 240.675974] CR2: 00007f966b346000 CR3: 0000000168cea002 CR4: 00000000003706e0
> [ 240.683807] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> [ 240.691641] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
> [ 240.699468] Call Trace:
> [ 240.702613] <TASK>
> [ 240.705413] page_counter_uncharge+0x29/0x80
> [ 240.710389] drain_stock+0xd0/0x180
> [ 240.714585] refill_stock+0x278/0x580
> [ 240.718951] __sk_mem_reduce_allocated+0x222/0x5c0
> [ 240.729248] __mptcp_update_rmem+0x235/0x2c0
> [ 240.734228] __mptcp_move_skbs+0x194/0x6c0
> [ 240.749764] mptcp_recvmsg+0xdfa/0x1340
> [ 240.763153] inet_recvmsg+0x37f/0x500
> [ 240.782109] sock_read_iter+0x24a/0x380
> [ 240.805353] new_sync_read+0x420/0x540
> [ 240.838552] vfs_read+0x37f/0x4c0
> [ 240.842582] ksys_read+0x170/0x200
> [ 240.864039] do_syscall_64+0x5c/0x80
> [ 240.872770] entry_SYSCALL_64_after_hwframe+0x46/0xb0
> [ 240.878526] RIP: 0033:0x7f3786d9ae8e
> [ 240.882805] Code: c0 e9 b6 fe ff ff 50 48 8d 3d 6e 18 0a 00 e8 89 e8 01 00 66 0f 1f 84 00 00 00 00 00 64 8b 04 25 18 00 00 00 85 c0 75 14 0f 05 <48> 3d 00 f0 ff ff 77 5a c3 66 0f 1f 84 00 00 00 00 00 48 83 ec 28
> [ 240.902259] RSP: 002b:00007fff7be81e08 EFLAGS: 00000246 ORIG_RAX: 0000000000000000
> [ 240.910533] RAX: ffffffffffffffda RBX: 0000000000002000 RCX: 00007f3786d9ae8e
> [ 240.918368] RDX: 0000000000002000 RSI: 00007fff7be87ec0 RDI: 0000000000000005
> [ 240.926206] RBP: 0000000000000005 R08: 00007f3786e6a230 R09: 00007f3786e6a240
> [ 240.934046] R10: fffffffffffff288 R11: 0000000000000246 R12: 0000000000002000
> [ 240.941884] R13: 00007fff7be87ec0 R14: 00007fff7be87ec0 R15: 0000000000002000
> [ 240.949741] </TASK>
> [ 240.952632] irq event stamp: 27367
> [ 240.956735] hardirqs last enabled at (27366): [<ffffffff81ba50ea>] mem_cgroup_uncharge_skmem+0x6a/0x80
> [ 240.966848] hardirqs last disabled at (27367): [<ffffffff81b8fd42>] refill_stock+0x282/0x580
> [ 240.976017] softirqs last enabled at (27360): [<ffffffff83a4d8ef>] mptcp_recvmsg+0xaf/0x1340
> [ 240.985273] softirqs last disabled at (27364): [<ffffffff83a4d30c>] __mptcp_move_skbs+0x18c/0x6c0
> [ 240.994872] ---[ end trace 0000000000000000 ]---
>
> [...]
Here is the summary with links:
- [net,1/2] mptcp: fix fwd memory accounting on coalesce
https://git.kernel.org/netdev/net/c/7288ff6ec795
- [net,2/2] Documentation: mptcp: fix pm_type formatting
https://git.kernel.org/netdev/net/c/0727a9a5fbc1
You are awesome, thank you!
--
Deet-doot-dot, I am a bot.
https://korg.docs.kernel.org/patchwork/pwbot.html
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2022-09-13 8:30 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
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2022-09-06 18:04 [PATCH net 1/2] mptcp: fix fwd memory accounting on coalesce Matthieu Baerts
2022-09-06 18:04 ` [PATCH net 2/2] Documentation: mptcp: fix pm_type formatting Matthieu Baerts
2022-09-06 18:04 ` [PATCH net 0/2] mptcp: fix fwd memory accounting and doc format Matthieu Baerts
2022-09-13 8:30 ` [PATCH net 1/2] mptcp: fix fwd memory accounting on coalesce patchwork-bot+netdevbpf
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