From 64c00d81b5c2491bd140b3c8eb2e8c351513f971 Mon Sep 17 00:00:00 2001 From: Andrew Gallatin Date: Wed, 13 Aug 2008 15:16:00 -0700 Subject: [PATCH] pktgen: prevent pktgen from using bad tx queue With the new multi-queue transmit code, it is possible to accidentally make pktgen pick a non-existing tx queue simply by using a stale script to drive pktgen. Access to this non-existing tx queue will then trigger a bad memory access and kill the machine. For example, setting "queue_map_max 2" will cause my machine to die when accessing a garbage spinlock in the non-existing tx queue: BUG: spinlock bad magic on CPU#0, kpktgend_0/564 lock: ffff88001ddf6718, .magic: ffffffff, .owner: /-1, .owner_cpu: 0 Pid: 564, comm: kpktgend_0 Not tainted 2.6.27-rc3 #35 Call Trace: [] spin_bug+0xa4/0xac [] _raw_spin_lock+0x23/0x123 [] _spin_lock_bh+0x17/0x1b [] pktgen_thread_worker+0xa97/0x1002 [] ? finish_task_switch+0x38/0x97 [] ? autoremove_wake_function+0x0/0x36 [] ? autoremove_wake_function+0x0/0x36 [] ? pktgen_thread_worker+0x0/0x1002 [] kthread+0x44/0x6d [] child_rip+0xa/0x11 [] ? kthread+0x0/0x6d [] ? child_rip+0x0/0x11 The attached patch adds some sanity checking to prevent these sorts of configuration errors. Signed-off-by: Andrew Gallatin Signed-off-by: David S. Miller --- net/core/pktgen.c | 29 +++++++++++++++++++++++++++++ 1 file changed, 29 insertions(+) diff --git a/net/core/pktgen.c b/net/core/pktgen.c index 5262364539..a756847e38 100644 --- a/net/core/pktgen.c +++ b/net/core/pktgen.c @@ -1961,6 +1961,8 @@ static int pktgen_setup_dev(struct pktgen_dev *pkt_dev, const char *ifname) */ static void pktgen_setup_inject(struct pktgen_dev *pkt_dev) { + int ntxq; + if (!pkt_dev->odev) { printk(KERN_ERR "pktgen: ERROR: pkt_dev->odev == NULL in " "setup_inject.\n"); @@ -1969,6 +1971,33 @@ static void pktgen_setup_inject(struct pktgen_dev *pkt_dev) return; } + /* make sure that we don't pick a non-existing transmit queue */ + ntxq = pkt_dev->odev->real_num_tx_queues; + if (ntxq <= num_online_cpus() && (pkt_dev->flags & F_QUEUE_MAP_CPU)) { + printk(KERN_WARNING "pktgen: WARNING: QUEUE_MAP_CPU " + "disabled because CPU count (%d) exceeds number ", + num_online_cpus()); + printk(KERN_WARNING "pktgen: WARNING: of tx queues " + "(%d) on %s \n", ntxq, pkt_dev->odev->name); + pkt_dev->flags &= ~F_QUEUE_MAP_CPU; + } + if (ntxq <= pkt_dev->queue_map_min) { + printk(KERN_WARNING "pktgen: WARNING: Requested " + "queue_map_min (%d) exceeds number of tx\n", + pkt_dev->queue_map_min); + printk(KERN_WARNING "pktgen: WARNING: queues (%d) on " + "%s, resetting\n", ntxq, pkt_dev->odev->name); + pkt_dev->queue_map_min = ntxq - 1; + } + if (ntxq <= pkt_dev->queue_map_max) { + printk(KERN_WARNING "pktgen: WARNING: Requested " + "queue_map_max (%d) exceeds number of tx\n", + pkt_dev->queue_map_max); + printk(KERN_WARNING "pktgen: WARNING: queues (%d) on " + "%s, resetting\n", ntxq, pkt_dev->odev->name); + pkt_dev->queue_map_max = ntxq - 1; + } + /* Default to the interface's mac if not explicitly set. */ if (is_zero_ether_addr(pkt_dev->src_mac)) -- 2.39.5