diff options
| author | Amery Hung <ameryhung@gmail.com> | 2025-05-02 13:16:20 -0700 |
|---|---|---|
| committer | Martin KaFai Lau <martin.lau@kernel.org> | 2025-05-02 14:50:08 -0700 |
| commit | 659b3b2c488532140676affef036a1702fde6e32 (patch) | |
| tree | 322243467c79a00e446fcf1d240da3d1c72eba27 /net/sched | |
| parent | 1b1f563a2526625a9125c1a63f47239f40f5e259 (diff) | |
bpf: net_sched: Fix bpf qdisc init prologue when set as default qdisc
Allow .init to proceed if qdisc_lookup() returns NULL as it only happens
when called by qdisc_create_dflt() in mq/mqprio_init and the parent qdisc
has not been added to qdisc_hash yet. In qdisc_create(), the caller,
__tc_modify_qdisc(), would have made sure the parent qdisc already exist.
In addition, call qdisc_watchdog_init() whether .init succeeds or not to
prevent null-pointer dereference. In qdisc_create() and
qdisc_create_dflt(), if .init fails, .destroy will be called. As a
result, the destroy epilogue could call qdisc_watchdog_cancel() with an
uninitialized timer, causing null-pointer deference in hrtimer_cancel().
Fixes: c8240344956e ("bpf: net_sched: Support implementation of Qdisc_ops in bpf")
Signed-off-by: Amery Hung <ameryhung@gmail.com>
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Diffstat (limited to 'net/sched')
| -rw-r--r-- | net/sched/bpf_qdisc.c | 12 |
1 files changed, 7 insertions, 5 deletions
diff --git a/net/sched/bpf_qdisc.c b/net/sched/bpf_qdisc.c index 9f32b305636fc..a8efc3ff2b7e4 100644 --- a/net/sched/bpf_qdisc.c +++ b/net/sched/bpf_qdisc.c @@ -234,18 +234,20 @@ __bpf_kfunc int bpf_qdisc_init_prologue(struct Qdisc *sch, struct net_device *dev = qdisc_dev(sch); struct Qdisc *p; + qdisc_watchdog_init(&q->watchdog, sch); + if (sch->parent != TC_H_ROOT) { + /* If qdisc_lookup() returns NULL, it means .init is called by + * qdisc_create_dflt() in mq/mqprio_init and the parent qdisc + * has not been added to qdisc_hash yet. + */ p = qdisc_lookup(dev, TC_H_MAJ(sch->parent)); - if (!p) - return -ENOENT; - - if (!(p->flags & TCQ_F_MQROOT)) { + if (p && !(p->flags & TCQ_F_MQROOT)) { NL_SET_ERR_MSG(extack, "BPF qdisc only supported on root or mq"); return -EINVAL; } } - qdisc_watchdog_init(&q->watchdog, sch); return 0; } |