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ANDROID: netlink: add netlink poll and hooks

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In huge uevents generating system, especially for user apps who have
small size of rcvbuf socket, it has been reported that netlink overrun
happens quite frequently.

Moreover, if there's no POLLERR (caused by this netlink overrun) handler
in user apps, the system can almost be stucked by calling 'poll' repeatedly.

Regarding this issue, I have sent a kernel netlink patch to linux
maintainers and got replied that this is absolutely user app's problem,
must not addressing kernel.

Until Android team look into this issue and some modification comes out,
we need kernel patch for temporary. To minimize the effect by this patch
to the others who have never met this issue, I would like to just add
netlink's dedicated poll and its hooks.

Please refer to below v1/v2 patch links for history.

v1: https://lore.kernel.org/netdev/20231110110002.7279f895@kernel.org/T/#t
v2: https://lore.kernel.org/netdev/d599922fd89b3e61c7cf531a03ea8b81cbcb003e.camel@redhat.com/T/#t

Bug: 300009377
Link: https://lore.kernel.org/netdev/d599922fd89b3e61c7cf531a03ea8b81cbcb003e.camel@redhat.com/T/#t

Change-Id: I4f11399d61c10332ba05bac64cfa1e92bb111565
Signed-off-by: Jong eon Park <jongeon.park@samsung.com>
This commit is contained in:
Jong eon Park 2023-11-29 16:50:44 +09:00 committed by Treehugger Robot
parent c9b5c232e7
commit ddf142e5a8
3 changed files with 20 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
drivers/android/vendor_hooks.c
View File

@ -364,3 +364,4 @@ EXPORT_TRACEPOINT_SYMBOL_GPL(android_vh_mmc_blk_mq_rw_recovery);
EXPORT_TRACEPOINT_SYMBOL_GPL(android_vh_sd_update_bus_speed_mode);
EXPORT_TRACEPOINT_SYMBOL_GPL(android_vh_slab_folio_alloced);
EXPORT_TRACEPOINT_SYMBOL_GPL(android_vh_kmalloc_large_alloced);
EXPORT_TRACEPOINT_SYMBOL_GPL(android_vh_netlink_poll);

7
include/trace/hooks/net.h
View File

@ -25,6 +25,13 @@ DECLARE_RESTRICTED_HOOK(android_rvh_sk_alloc,
DECLARE_RESTRICTED_HOOK(android_rvh_sk_free,
TP_PROTO(struct sock *sock), TP_ARGS(sock), 1);
struct poll_table_struct;
typedef struct poll_table_struct poll_table;
DECLARE_HOOK(android_vh_netlink_poll,
TP_PROTO(struct file *file, struct socket *sock, poll_table *wait,
__poll_t *mask),
TP_ARGS(file, sock, wait, mask));
/* macro versions of hooks are no longer required */
#endif /* _TRACE_HOOK_NET_VH_H */

14
net/netlink/af_netlink.c
View File

@ -71,7 +71,8 @@
#include <net/netlink.h>
#define CREATE_TRACE_POINTS
#include <trace/events/netlink.h>
#undef CREATE_TRACE_POINTS
#include <trace/hooks/net.h>
#include "af_netlink.h"
struct listeners {
@ -1966,6 +1967,15 @@ static int netlink_recvmsg(struct socket *sock, struct msghdr *msg, size_t len,
return err ? : copied;
}
static __poll_t netlink_poll(struct file *file, struct socket *sock,
poll_table *wait)
{
__poll_t mask = datagram_poll(file, sock, wait);
trace_android_vh_netlink_poll(file, sock, wait, &mask);
return mask;
}
static void netlink_data_ready(struct sock *sk)
{
BUG();
@ -2766,7 +2776,7 @@ static const struct proto_ops netlink_ops = {
.socketpair = sock_no_socketpair,
.accept = sock_no_accept,
.getname = netlink_getname,
.poll = datagram_poll,
.poll = netlink_poll,
.ioctl = netlink_ioctl,
.listen = sock_no_listen,
.shutdown = sock_no_shutdown,