Re: [PATCH net-next] netconsole: avoid a crash with multiple sysfs writers
From: Dan Aloni Date: Fri, 30 Aug 2013 13:59:46 +0300 > When my 'ifup eth' script was fired multiple times and ran concurrent on > my laptop, for some obscure /etc scripting reason, it was revealed > that the store_enabled() function in netconsole doesn't handle it nicely, > as recorded by the Oops below (a syslog paste, but not mangled too much > to prevent from discerning the traceback). > > On Linux 3.10.4, this patch seeks to remedy the problem, and it has been > running stable on my laptop for a few days. ... > Signed-off-by: Dan Aloni > Signed-off-by: Neil Horman Applied, thanks. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH net-next] netconsole: avoid a crash with multiple sysfs writers
From: Dan Aloni alo...@postram.com Date: Fri, 30 Aug 2013 13:59:46 +0300 When my 'ifup eth' script was fired multiple times and ran concurrent on my laptop, for some obscure /etc scripting reason, it was revealed that the store_enabled() function in netconsole doesn't handle it nicely, as recorded by the Oops below (a syslog paste, but not mangled too much to prevent from discerning the traceback). On Linux 3.10.4, this patch seeks to remedy the problem, and it has been running stable on my laptop for a few days. ... Signed-off-by: Dan Aloni alo...@postram.com Signed-off-by: Neil Horman nhor...@tuxdriver.com Applied, thanks. -- To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
[PATCH net-next] netconsole: avoid a crash with multiple sysfs writers
When my 'ifup eth' script was fired multiple times and ran concurrent on
my laptop, for some obscure /etc scripting reason, it was revealed
that the store_enabled() function in netconsole doesn't handle it nicely,
as recorded by the Oops below (a syslog paste, but not mangled too much
to prevent from discerning the traceback).
On Linux 3.10.4, this patch seeks to remedy the problem, and it has been
running stable on my laptop for a few days.
[52608.609325] BUG: unable to handle kernel NULL pointer dereference at
03e0
[52608.609331] IP: [] __netpoll_cleanup+0x27/0xe0
[52608.609339] PGD 15e51a067 PUD 15433e067 PMD 0
[52608.609343] Oops: [#1] SMP re firewire_ohci firewire_core crc_itu_t
[last unloaded: kvm_intel]
[52608.609347] Modules linked in: kvm_intel tun vfat fat ppdev parport_pc
parport fuse ipt_MASQUERADE usb_storage nf_conntrack_netbios_ns nf_conn
[..garbled..]
[52608.609433] RAX: RBX: 880210bbcc68 RCX:
[52608.609435] RDX: RSI: 8801ba447da0 RDI: 880210bbcc68
[52608.609437] RBP: 8801ba447e18 R08: R09: 0001
[52608.609439] R10: 000a R11: f000 R12: 880210bbcc68
[52608.609441] R13: 88020bc41000 R14: 0002 R15:
0002000
[52608.609443] FS: 7f38d7bff740() GS:88021dc4()
knlGS:
[52608.609446] CS: 0010 DS: ES: CR0: 80050033001427e0
[52608.609448] CR2: 03e0 CR3: 000154103000 CR4: 001427e0
[52608.609450] DR0: DR1: DR2:
[52608.609452] netpoll: netconsole: local port 6665ess 10.0.0.27
[52608.609454] netpoll: netconsole: local IPv4 address 10.0.0.27
[52608.609456] netpoll: netconsole: interface 'em1'
[52608.609457] netpoll: netconsole: remote port 514ress 10.0.0.15
[52608.609459] netpoll: netconsole: remote IPv4 address 10.0.0.15:65:a8:9a:c7
[52608.609461] netpoll: netconsole: remote ethernet address 1c:6f:65:a8:9a:c7
[52608.609463] DR3: DR6: 0ff0 DR7: 0400
[52608.609464] Stack:801ba447e08 880210bbcc68 ffea
88020bc41000
[52608.609466] 8801ba447e08 880210bbcc68 ffea
88020bc41000
[52608.609471] 0002 0002 8801ba447e38
81532af4
[52608.609475] 880210bbcc00 8801ba447e78
81420e7c
[52608.609479] Call Trace:
[52608.609484] [] netpoll_cleanup+0x24/0x50
[52608.609489] [] store_enabled+0x5c/0xe0
[52608.609492] [] netconsole_target_attr_store+0x2e/0x40
[52608.609498] [] configfs_write_file+0xd2/0x130
[52608.609503] [] vfs_write+0xc5/0x1f0
[52608.609506] [] SyS_write+0x52/0xa0/0x10
[52608.609511] [] ? do_page_fault+0xe/0x10
[52608.609516] [] system_call_fastpath+0x16/0x1b
[52608.609517] Code: 1f 44 00 00 0f 1f 44 00 00 55 48 89 e5 48 83 ec 30 4c 89
65 e0 48 89 5d d8 49 89 fc 4c 89 6d e8 4c 89 75 f0 4c 89 7d f8 48 8
[..garbled..]
[52608.609559] RIP [] __netpoll_cleanup+0x27/0xe0
[52608.609563] RSP
[52608.609564] CR2: 03e0
[52608.609567] ---[ end trace d25ec343349b61d2 ]---
Signed-off-by: Dan Aloni
Signed-off-by: Neil Horman
CC: David S. Miller
---
drivers/net/netconsole.c | 13 -
1 file changed, 12 insertions(+), 1 deletion(-)
diff --git a/drivers/net/netconsole.c b/drivers/net/netconsole.c
index 4822aaf..dcb2134 100644
--- a/drivers/net/netconsole.c
+++ b/drivers/net/netconsole.c
@@ -102,6 +102,7 @@ struct netconsole_target {
struct config_item item;
#endif
int enabled;
+ struct mutexmutex;
struct netpoll np;
};
@@ -181,6 +182,7 @@ static struct netconsole_target *alloc_param_target(char
*target_config)
strlcpy(nt->np.dev_name, "eth0", IFNAMSIZ);
nt->np.local_port = 6665;
nt->np.remote_port = ;
+ mutex_init(>mutex);
memset(nt->np.remote_mac, 0xff, ETH_ALEN);
/* Parse parameters and setup netpoll */
@@ -322,6 +324,7 @@ static ssize_t store_enabled(struct netconsole_target *nt,
return -EINVAL;
}
+ mutex_lock(>mutex);
if (enabled) { /* 1 */
/*
@@ -331,8 +334,10 @@ static ssize_t store_enabled(struct netconsole_target *nt,
netpoll_print_options(>np);
err = netpoll_setup(>np);
- if (err)
+ if (err) {
+ mutex_unlock(>mutex);
return err;
+ }
printk(KERN_INFO "netconsole: network logging started\n");
@@ -341,6 +346,7 @@ static ssize_t store_enabled(struct netconsole_target *nt,
}
nt->enabled = enabled;
+ mutex_unlock(>mutex);
return strnlen(buf, count);
}
@@ -597,6 +603,7 @@ static struct config_item *make_netconsole_target(struct
config_group *group,
[PATCH net-next] netconsole: avoid a crash with multiple sysfs writers
When my 'ifup eth' script was fired multiple times and ran concurrent on
my laptop, for some obscure /etc scripting reason, it was revealed
that the store_enabled() function in netconsole doesn't handle it nicely,
as recorded by the Oops below (a syslog paste, but not mangled too much
to prevent from discerning the traceback).
On Linux 3.10.4, this patch seeks to remedy the problem, and it has been
running stable on my laptop for a few days.
[52608.609325] BUG: unable to handle kernel NULL pointer dereference at
03e0
[52608.609331] IP: [81532a17] __netpoll_cleanup+0x27/0xe0
[52608.609339] PGD 15e51a067 PUD 15433e067 PMD 0
[52608.609343] Oops: [#1] SMP re firewire_ohci firewire_core crc_itu_t
[last unloaded: kvm_intel]
[52608.609347] Modules linked in: kvm_intel tun vfat fat ppdev parport_pc
parport fuse ipt_MASQUERADE usb_storage nf_conntrack_netbios_ns nf_conn
[..garbled..]
[52608.609433] RAX: RBX: 880210bbcc68 RCX:
[52608.609435] RDX: RSI: 8801ba447da0 RDI: 880210bbcc68
[52608.609437] RBP: 8801ba447e18 R08: R09: 0001
[52608.609439] R10: 000a R11: f000 R12: 880210bbcc68
[52608.609441] R13: 88020bc41000 R14: 0002 R15:
0002000
[52608.609443] FS: 7f38d7bff740() GS:88021dc4()
knlGS:
[52608.609446] CS: 0010 DS: ES: CR0: 80050033001427e0
[52608.609448] CR2: 03e0 CR3: 000154103000 CR4: 001427e0
[52608.609450] DR0: DR1: DR2:
[52608.609452] netpoll: netconsole: local port 6665ess 10.0.0.27
[52608.609454] netpoll: netconsole: local IPv4 address 10.0.0.27
[52608.609456] netpoll: netconsole: interface 'em1'
[52608.609457] netpoll: netconsole: remote port 514ress 10.0.0.15
[52608.609459] netpoll: netconsole: remote IPv4 address 10.0.0.15:65:a8:9a:c7
[52608.609461] netpoll: netconsole: remote ethernet address 1c:6f:65:a8:9a:c7
[52608.609463] DR3: DR6: 0ff0 DR7: 0400
[52608.609464] Stack:801ba447e08 880210bbcc68 ffea
88020bc41000
[52608.609466] 8801ba447e08 880210bbcc68 ffea
88020bc41000
[52608.609471] 0002 0002 8801ba447e38
81532af4
[52608.609475] 880210bbcc00 8801ba447e78
81420e7c
[52608.609479] Call Trace:
[52608.609484] [81532af4] netpoll_cleanup+0x24/0x50
[52608.609489] [81420e7c] store_enabled+0x5c/0xe0
[52608.609492] [81420abe] netconsole_target_attr_store+0x2e/0x40
[52608.609498] [811ff2a2] configfs_write_file+0xd2/0x130
[52608.609503] [81188f95] vfs_write+0xc5/0x1f0
[52608.609506] [81189482] SyS_write+0x52/0xa0/0x10
[52608.609511] [81628c2e] ? do_page_fault+0xe/0x10
[52608.609516] [8162d402] system_call_fastpath+0x16/0x1b
[52608.609517] Code: 1f 44 00 00 0f 1f 44 00 00 55 48 89 e5 48 83 ec 30 4c 89
65 e0 48 89 5d d8 49 89 fc 4c 89 6d e8 4c 89 75 f0 4c 89 7d f8 48 8
[..garbled..]
[52608.609559] RIP [81532a17] __netpoll_cleanup+0x27/0xe0
[52608.609563] RSP 8801ba447de8
[52608.609564] CR2: 03e0
[52608.609567] ---[ end trace d25ec343349b61d2 ]---
Signed-off-by: Dan Aloni alo...@postram.com
Signed-off-by: Neil Horman nhor...@tuxdriver.com
CC: David S. Miller da...@davemloft.net
---
drivers/net/netconsole.c | 13 -
1 file changed, 12 insertions(+), 1 deletion(-)
diff --git a/drivers/net/netconsole.c b/drivers/net/netconsole.c
index 4822aaf..dcb2134 100644
--- a/drivers/net/netconsole.c
+++ b/drivers/net/netconsole.c
@@ -102,6 +102,7 @@ struct netconsole_target {
struct config_item item;
#endif
int enabled;
+ struct mutexmutex;
struct netpoll np;
};
@@ -181,6 +182,7 @@ static struct netconsole_target *alloc_param_target(char
*target_config)
strlcpy(nt-np.dev_name, eth0, IFNAMSIZ);
nt-np.local_port = 6665;
nt-np.remote_port = ;
+ mutex_init(nt-mutex);
memset(nt-np.remote_mac, 0xff, ETH_ALEN);
/* Parse parameters and setup netpoll */
@@ -322,6 +324,7 @@ static ssize_t store_enabled(struct netconsole_target *nt,
return -EINVAL;
}
+ mutex_lock(nt-mutex);
if (enabled) { /* 1 */
/*
@@ -331,8 +334,10 @@ static ssize_t store_enabled(struct netconsole_target *nt,
netpoll_print_options(nt-np);
err = netpoll_setup(nt-np);
- if (err)
+ if (err) {
+ mutex_unlock(nt-mutex);
return err;
+ }
printk(KERN_INFO netconsole: network logging started\n);
@@ -341,6 +346,7 @@ static ssize_t store_enabled(struct
