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| author | Andrew Gallatin <gallatin@myri.com> | 2008-08-13 15:16:00 -0700 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2008-08-13 15:16:00 -0700 |
| commit | 64c00d81b5c2491bd140b3c8eb2e8c351513f971 (patch) | |
| tree | 28f2122cab0dc9d1e228a96aedd178ed53f12456 /net | |
| parent | 3e8a0a559c66ee9e7468195691a56fefc3589740 (diff) | |
| download | lwn-64c00d81b5c2491bd140b3c8eb2e8c351513f971.tar.gz lwn-64c00d81b5c2491bd140b3c8eb2e8c351513f971.zip | |
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:
[<ffffffff803a1228>] spin_bug+0xa4/0xac
[<ffffffff803a1253>] _raw_spin_lock+0x23/0x123
[<ffffffff8055b06f>] _spin_lock_bh+0x17/0x1b
[<ffffffff804cb57d>] pktgen_thread_worker+0xa97/0x1002
[<ffffffff8022874d>] ? finish_task_switch+0x38/0x97
[<ffffffff80242077>] ? autoremove_wake_function+0x0/0x36
[<ffffffff80242077>] ? autoremove_wake_function+0x0/0x36
[<ffffffff804caae6>] ? pktgen_thread_worker+0x0/0x1002
[<ffffffff80241a40>] kthread+0x44/0x6d
[<ffffffff8020c399>] child_rip+0xa/0x11
[<ffffffff802419fc>] ? kthread+0x0/0x6d
[<ffffffff8020c38f>] ? child_rip+0x0/0x11
The attached patch adds some sanity checking to prevent
these sorts of configuration errors.
Signed-off-by: Andrew Gallatin <gallatin@myri.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net')
| -rw-r--r-- | net/core/pktgen.c | 29 |
1 files changed, 29 insertions, 0 deletions
diff --git a/net/core/pktgen.c b/net/core/pktgen.c index 526236453908..a756847e3814 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)) |