diff options
| author | Sabrina Dubroca <sd@queasysnail.net> | 2025-05-23 17:11:18 +0200 |
|---|---|---|
| committer | Steffen Klassert <steffen.klassert@secunet.com> | 2025-06-03 15:39:57 +0200 |
| commit | 7eb11c0ab70777b9e5145a5ba1c0a2312c3980b2 (patch) | |
| tree | 1b2bbdde98c7f1f4ca6f253be5edf1dace39c150 | |
| parent | 94d077c331730510d5611b438640a292097341f0 (diff) | |
| download | ipsec-7eb11c0ab70777b9e5145a5ba1c0a2312c3980b2.tar.gz | |
xfrm: state: use a consistent pcpu_id in xfrm_state_find
If we get preempted during xfrm_state_find, we could run
xfrm_state_look_at using a different pcpu_id than the one
xfrm_state_find saw. This could lead to ignoring states that should
have matched, and triggering acquires on a CPU that already has a pcpu
state.
xfrm_state_find starts on CPU1
pcpu_id = 1
lookup starts
<preemption, we're now on CPU2>
xfrm_state_look_at pcpu_id = 2
finds a state
found:
best->pcpu_num != pcpu_id (2 != 1)
if (!x && !error && !acquire_in_progress) {
...
xfrm_state_alloc
xfrm_init_tempstate
...
This can be avoided by passing the original pcpu_id down to all
xfrm_state_look_at() calls.
Also switch to raw_smp_processor_id, disabling preempting just to
re-enable it immediately doesn't really make sense.
Fixes: 1ddf9916ac09 ("xfrm: Add support for per cpu xfrm state handling.")
Signed-off-by: Sabrina Dubroca <sd@queasysnail.net>
Reviewed-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
| -rw-r--r-- | net/xfrm/xfrm_state.c | 19 |
1 files changed, 6 insertions, 13 deletions
diff --git a/net/xfrm/xfrm_state.c b/net/xfrm/xfrm_state.c index 2e2e95d2a06fce..7e34fc94f668b2 100644 --- a/net/xfrm/xfrm_state.c +++ b/net/xfrm/xfrm_state.c @@ -1307,14 +1307,8 @@ static void xfrm_hash_grow_check(struct net *net, int have_hash_collision) static void xfrm_state_look_at(struct xfrm_policy *pol, struct xfrm_state *x, const struct flowi *fl, unsigned short family, struct xfrm_state **best, int *acq_in_progress, - int *error) + int *error, unsigned int pcpu_id) { - /* We need the cpu id just as a lookup key, - * we don't require it to be stable. - */ - unsigned int pcpu_id = get_cpu(); - put_cpu(); - /* Resolution logic: * 1. There is a valid state with matching selector. Done. * 2. Valid state with inappropriate selector. Skip. @@ -1381,8 +1375,7 @@ xfrm_state_find(const xfrm_address_t *daddr, const xfrm_address_t *saddr, /* We need the cpu id just as a lookup key, * we don't require it to be stable. */ - pcpu_id = get_cpu(); - put_cpu(); + pcpu_id = raw_smp_processor_id(); to_put = NULL; @@ -1402,7 +1395,7 @@ xfrm_state_find(const xfrm_address_t *daddr, const xfrm_address_t *saddr, tmpl->id.proto == x->id.proto && (tmpl->id.spi == x->id.spi || !tmpl->id.spi)) xfrm_state_look_at(pol, x, fl, encap_family, - &best, &acquire_in_progress, &error); + &best, &acquire_in_progress, &error, pcpu_id); } if (best) @@ -1419,7 +1412,7 @@ xfrm_state_find(const xfrm_address_t *daddr, const xfrm_address_t *saddr, tmpl->id.proto == x->id.proto && (tmpl->id.spi == x->id.spi || !tmpl->id.spi)) xfrm_state_look_at(pol, x, fl, family, - &best, &acquire_in_progress, &error); + &best, &acquire_in_progress, &error, pcpu_id); } cached: @@ -1460,7 +1453,7 @@ cached: tmpl->id.proto == x->id.proto && (tmpl->id.spi == x->id.spi || !tmpl->id.spi)) xfrm_state_look_at(pol, x, fl, family, - &best, &acquire_in_progress, &error); + &best, &acquire_in_progress, &error, pcpu_id); } if (best || acquire_in_progress) goto found; @@ -1495,7 +1488,7 @@ cached: tmpl->id.proto == x->id.proto && (tmpl->id.spi == x->id.spi || !tmpl->id.spi)) xfrm_state_look_at(pol, x, fl, family, - &best, &acquire_in_progress, &error); + &best, &acquire_in_progress, &error, pcpu_id); } found: |