On Thu, Oct 22, 2020 at 01:00:16PM +0200, Peter Zijlstra wrote: > On Thu, Oct 22, 2020 at 12:21:55PM +0300, Anatoly Pugachev wrote: > > Hello! > > > > Bisected the following linux calltrace after v5.9 : > > > > [ 8.650198] systemd[1]: Started Journal Service. > > [ 9.028125] ------------[ cut here ]------------ > > [ 9.028171] WARNING: CPU: 11 PID: 499 at > > net/netfilter/nf_tables_api.c:622 nft_chain_parse_hook+0x7c/0x360 > > [nf_tables] > > [ 9.028185] Modules linked in: nf_tables nfnetlink sunrpc ip_tables > > x_tables ipv6 crc_ccitt autofs4 ext4 crc16 mbcache jbd2 raid10 raid456 > > async_raid6_recov async_mem > > cpy async_pq async_xor xor async_tx raid6_pq raid1 raid0 multipath > > linear md_mod crc32c_sparc64 > > [ 9.028243] CPU: 11 PID: 499 Comm: nft Tainted: G W > > 5.9.0-rc8-00209-gbaffd723e44d #111 > > [ 9.028255] Call Trace: > > [ 9.028269] [<00000000004727e8>] __warn+0xa8/0x120 > > [ 9.028278] [<0000000000472c20>] warn_slowpath_fmt+0x34/0x74 > > [ 9.028291] [<00000000100c19fc>] nft_chain_parse_hook+0x7c/0x360 [nf_tables] > > > commit 4d004099a668c41522242aa146a38cc4eb59cb1e > > What's unexpected.. while I just queued a another fix for that commit: > > https://lkml.kernel.org/r/20201022103028.GC2611@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx > > I don't think that explains this WARN. Let me go prod at it. This looks like lockdep_is_held() encounters an incremented recursion count and returns 1, which in this case will trigger the WARN. But that would mean we're leaking a recursion count somewhere... do you have CONFIG_DEBUG_PREEMPT enabled?
