From 2c8a01894a12665d8059fad8f0a293c98a264121 Mon Sep 17 00:00:00 2001 From: dingtianhong Date: Thu, 11 Jul 2013 19:04:02 +0800 Subject: [PATCH] dummy: fix oops when loading the dummy failed We rename the dummy in modprobe.conf like this: install dummy0 /sbin/modprobe -o dummy0 --ignore-install dummy install dummy1 /sbin/modprobe -o dummy1 --ignore-install dummy We got oops when we run the command: modprobe dummy0 modprobe dummy1 ------------[ cut here ]------------ [ 3302.187584] BUG: unable to handle kernel NULL pointer dereference at 0000000000000008 [ 3302.195411] IP: [] __rtnl_link_unregister+0x9a/0xd0 [ 3302.201844] PGD 85c94a067 PUD 8517bd067 PMD 0 [ 3302.206305] Oops: 0002 [#1] SMP [ 3302.299737] task: ffff88105ccea300 ti: ffff880eba4a0000 task.ti: ffff880eba4a0000 [ 3302.307186] RIP: 0010:[] [] __rtnl_link_unregister+0x9a/0xd0 [ 3302.316044] RSP: 0018:ffff880eba4a1dd8 EFLAGS: 00010246 [ 3302.321332] RAX: 0000000000000000 RBX: ffffffff81a9d738 RCX: 0000000000000002 [ 3302.328436] RDX: 0000000000000000 RSI: ffffffffa04d602c RDI: ffff880eba4a1dd8 [ 3302.335541] RBP: ffff880eba4a1e18 R08: dead000000200200 R09: dead000000100100 [ 3302.342644] R10: 0000000000000080 R11: 0000000000000003 R12: ffffffff81a9d788 [ 3302.349748] R13: ffffffffa04d7020 R14: ffffffff81a9d670 R15: ffff880eba4a1dd8 [ 3302.364910] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 3302.370630] CR2: 0000000000000008 CR3: 000000085e15e000 CR4: 00000000000427e0 [ 3302.377734] DR0: 0000000000000003 DR1: 00000000000000b0 DR2: 0000000000000001 [ 3302.384838] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 [ 3302.391940] Stack: [ 3302.393944] ffff880eba4a1dd8 ffff880eba4a1dd8 ffff880eba4a1e18 ffffffffa04d70c0 [ 3302.401350] 00000000ffffffef ffffffffa01a8000 0000000000000000 ffffffff816111c8 [ 3302.408758] ffff880eba4a1e48 ffffffffa01a80be ffff880eba4a1e48 ffffffffa04d70c0 [ 3302.416164] Call Trace: [ 3302.418605] [] ? 0xffffffffa01a7fff [ 3302.423727] [] dummy_init_module+0xbe/0x1000 [dummy0] [ 3302.430405] [] ? 0xffffffffa01a7fff [ 3302.435535] [] do_one_initcall+0x152/0x1b0 [ 3302.441263] [] do_init_module+0x7b/0x200 [ 3302.446824] [] load_module+0x4e2/0x530 [ 3302.452215] [] ? ddebug_dyndbg_boot_param_cb+0x60/0x60 [ 3302.458979] [] SyS_init_module+0xd1/0x130 [ 3302.464627] [] system_call_fastpath+0x16/0x1b [ 3302.490090] RIP [] __rtnl_link_unregister+0x9a/0xd0 [ 3302.496607] RSP [ 3302.500084] CR2: 0000000000000008 [ 3302.503466] ---[ end trace 8342d49cd49f78ed ]--- The reason is that when loading dummy, if __rtnl_link_register() return failed, the init_module should return and avoid take the wrong path. Signed-off-by: Tan Xiaojun Signed-off-by: Ding Tianhong Signed-off-by: David S. Miller --- drivers/net/dummy.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/drivers/net/dummy.c b/drivers/net/dummy.c index 42aa54af6842..b710c6b2d659 100644 --- a/drivers/net/dummy.c +++ b/drivers/net/dummy.c @@ -185,6 +185,8 @@ static int __init dummy_init_module(void) rtnl_lock(); err = __rtnl_link_register(&dummy_link_ops); + if (err < 0) + goto out; for (i = 0; i < numdummies && !err; i++) { err = dummy_init_one(); @@ -192,6 +194,8 @@ static int __init dummy_init_module(void) } if (err < 0) __rtnl_link_unregister(&dummy_link_ops); + +out: rtnl_unlock(); return err; -- 2.20.1