From: YueHaibing yuehaibing@huawei.com
[ Upstream commit 3ebe1bca58c85325c97a22d4fc3f5b5420752e6f ]
BUG: unable to handle kernel paging request at ffffffffa018f000 PGD 3270067 P4D 3270067 PUD 3271063 PMD 2307eb067 PTE 0 Oops: 0000 [#1] PREEMPT SMP CPU: 0 PID: 4138 Comm: modprobe Not tainted 5.1.0-rc7+ #1 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.9.3-0-ge2fc41e-prebuilt.qemu-project.org 04/01/2014 RIP: 0010:ppp_register_compressor+0x3e/0xd0 [ppp_generic] Code: 98 4a 3f e2 48 8b 15 c1 67 00 00 41 8b 0c 24 48 81 fa 40 f0 19 a0 75 0e eb 35 48 8b 12 48 81 fa 40 f0 19 a0 74 RSP: 0018:ffffc90000d93c68 EFLAGS: 00010287 RAX: ffffffffa018f000 RBX: ffffffffa01a3000 RCX: 000000000000001a RDX: ffff888230c750a0 RSI: 0000000000000000 RDI: ffffffffa019f000 RBP: ffffc90000d93c80 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: ffffffffa0194080 R13: ffff88822ee1a700 R14: 0000000000000000 R15: ffffc90000d93e78 FS: 00007f2339557540(0000) GS:ffff888237a00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffffffffa018f000 CR3: 000000022bde4000 CR4: 00000000000006f0 Call Trace: ? 0xffffffffa01a3000 deflate_init+0x11/0x1000 [ppp_deflate] ? 0xffffffffa01a3000 do_one_initcall+0x6c/0x3cc ? kmem_cache_alloc_trace+0x248/0x3b0 do_init_module+0x5b/0x1f1 load_module+0x1db1/0x2690 ? m_show+0x1d0/0x1d0 __do_sys_finit_module+0xc5/0xd0 __x64_sys_finit_module+0x15/0x20 do_syscall_64+0x6b/0x1d0 entry_SYSCALL_64_after_hwframe+0x49/0xbe
If ppp_deflate fails to register in deflate_init, module initialization failed out, however ppp_deflate_draft may has been regiestred and not unregistered before return. Then the seconed modprobe will trigger crash like this.
Reported-by: Hulk Robot hulkci@huawei.com Signed-off-by: YueHaibing yuehaibing@huawei.com Acked-by: Guillaume Nault gnault@redhat.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/net/ppp/ppp_deflate.c | 20 ++++++++++++++------ 1 file changed, 14 insertions(+), 6 deletions(-)
--- a/drivers/net/ppp/ppp_deflate.c +++ b/drivers/net/ppp/ppp_deflate.c @@ -610,12 +610,20 @@ static struct compressor ppp_deflate_dra
static int __init deflate_init(void) { - int answer = ppp_register_compressor(&ppp_deflate); - if (answer == 0) - printk(KERN_INFO - "PPP Deflate Compression module registered\n"); - ppp_register_compressor(&ppp_deflate_draft); - return answer; + int rc; + + rc = ppp_register_compressor(&ppp_deflate); + if (rc) + return rc; + + rc = ppp_register_compressor(&ppp_deflate_draft); + if (rc) { + ppp_unregister_compressor(&ppp_deflate); + return rc; + } + + pr_info("PPP Deflate Compression module registered\n"); + return 0; }
static void __exit deflate_cleanup(void)