Message ID | 20220516085552.212616-1-pablo@netfilter.org |
---|---|
State | Changes Requested |
Delegated to: | Pablo Neira |
Headers | show |
Series | [nf] netfilter: nft_numgen: disable preempt to access per-cpu data | expand |
On Mon, May 16, 2022 at 10:55:52AM +0200, Pablo Neira Ayuso wrote: > [233241.951068] BUG: using smp_processor_id() in preemptible [00000000] code: nginx/2725 > [233241.951220] caller is nft_ng_random_eval+0x24/0x54 [nft_numgen] > [233241.951225] CPU: 2 PID: 2725 Comm: nginx Tainted: G OE 5.16.0-0.bpo.4-amd64 #1 Debian 5.16.12-1~bpo11+1 > [233241.951227] Hardware name: Supermicro SYS-5039MC-H8TRF/X11SCD-F, BIOS 1.7 11/23/2021 > [233241.951228] Call Trace: > [233241.951231] <TASK> > [233241.951233] dump_stack_lvl+0x48/0x5e > [233241.951236] check_preemption_disabled+0xde/0xe0 > [233241.951239] nft_ng_random_eval+0x24/0x54 [nft_numgen] For the record, patch applied to nf.git
On Wed, May 18, 2022 at 04:03:00PM +0200, Pablo Neira Ayuso wrote: > On Mon, May 16, 2022 at 10:55:52AM +0200, Pablo Neira Ayuso wrote: > > [233241.951068] BUG: using smp_processor_id() in preemptible [00000000] code: nginx/2725 > > [233241.951220] caller is nft_ng_random_eval+0x24/0x54 [nft_numgen] > > [233241.951225] CPU: 2 PID: 2725 Comm: nginx Tainted: G OE 5.16.0-0.bpo.4-amd64 #1 Debian 5.16.12-1~bpo11+1 > > [233241.951227] Hardware name: Supermicro SYS-5039MC-H8TRF/X11SCD-F, BIOS 1.7 11/23/2021 > > [233241.951228] Call Trace: > > [233241.951231] <TASK> > > [233241.951233] dump_stack_lvl+0x48/0x5e > > [233241.951236] check_preemption_disabled+0xde/0xe0 > > [233241.951239] nft_ng_random_eval+0x24/0x54 [nft_numgen] > > For the record, patch applied to nf.git I don't think my patch is correct, I should disable_bh instead. I kept it back.
diff --git a/net/netfilter/nft_numgen.c b/net/netfilter/nft_numgen.c index 81b40c663d86..78f860555c76 100644 --- a/net/netfilter/nft_numgen.c +++ b/net/netfilter/nft_numgen.c @@ -137,10 +137,15 @@ struct nft_ng_random { static u32 nft_ng_random_gen(struct nft_ng_random *priv) { - struct rnd_state *state = this_cpu_ptr(&nft_numgen_prandom_state); + struct rnd_state *state; + u32 ret; - return reciprocal_scale(prandom_u32_state(state), priv->modulus) + - priv->offset; + preempt_disable(); + state = this_cpu_ptr(&nft_numgen_prandom_state); + ret = reciprocal_scale(prandom_u32_state(state), priv->modulus) + priv->offset; + preempt_enable(); + + return ret; } static void nft_ng_random_eval(const struct nft_expr *expr,
[233241.951068] BUG: using smp_processor_id() in preemptible [00000000] code: nginx/2725 [233241.951220] caller is nft_ng_random_eval+0x24/0x54 [nft_numgen] [233241.951225] CPU: 2 PID: 2725 Comm: nginx Tainted: G OE 5.16.0-0.bpo.4-amd64 #1 Debian 5.16.12-1~bpo11+1 [233241.951227] Hardware name: Supermicro SYS-5039MC-H8TRF/X11SCD-F, BIOS 1.7 11/23/2021 [233241.951228] Call Trace: [233241.951231] <TASK> [233241.951233] dump_stack_lvl+0x48/0x5e [233241.951236] check_preemption_disabled+0xde/0xe0 [233241.951239] nft_ng_random_eval+0x24/0x54 [nft_numgen] Fixes: 978d8f9055c3 ("netfilter: nft_numgen: add map lookups for numgen random operations") Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org> --- See https://bugzilla.netfilter.org/show_bug.cgi?id=1603 net/netfilter/nft_numgen.c | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-)