On Thu, 2 Jan 2020 at 12:24, Naresh Kamboju <naresh.kamboju@xxxxxxxxxx> wrote: > > Results from Linaro’s test farm. > Regressions on arm64, arm, x86_64, and i386. > > While running LTP syscalls accept* test cases on stable-rc-4.19 branch kernel. > This report log extracted from qemu_x86_64. > > metadata: > git branch: linux-4.19.y > git repo: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable-rc.git > git commit: 4e040169e8b7f4e1c50ceb0f6596015ecc67a052 > git describe: v4.19.92-112-g4e040169e8b7 > make_kernelversion: 4.19.93-rc1 > kernel-config: > http://snapshots.linaro.org/openembedded/lkft/lkft/sumo/intel-corei7-64/lkft/linux-stable-rc-4.19/396/config > > Crash log, > > BUG: unable to handle kernel paging request at 0000000040000001 > [ 23.578222] PGD 138f25067 P4D 138f25067 PUD 0 > er run is 0h 15m[ 23.578222] Oops: 0000 [#1] SMP NOPTI > [ 23.578222] CPU: 1 PID: 2216 Comm: accept02 Not tainted 4.19.93-rc1 #1 > [ 23.578222] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), > BIOS 1.12.0-1 04/01/2014 > [ 23.578222] RIP: 0010:__inet_lookup_listener+0x12d/0x300 Reverting below patch solve this kernel panic, tcp/dccp: fix possible race __inet_lookup_established() [ Upstream commit 8dbd76e79a16b45b2ccb01d2f2e08dbf64e71e40 ] Michal Kubecek and Firo Yang did a very nice analysis of crashes happening in __inet_lookup_established(). Since a TCP socket can go from TCP_ESTABLISH to TCP_LISTEN (via a close()/socket()/listen() cycle) without a RCU grace period, I should not have changed listeners linkage in their hash table. They must use the nulls protocol (Documentation/RCU/rculist_nulls.txt), so that a lookup can detect a socket in a hash list was moved in another one. Since we added code in commit d296ba60d8e2 ("soreuseport: Resolve merge conflict for v4/v6 ordering fix"), we have to add hlist_nulls_add_tail_rcu() helper. Fixes: 3b24d854cb35 ("tcp/dccp: do not touch listener sk_refcnt under synflood") Signed-off-by: Eric Dumazet <edumazet@xxxxxxxxxx> Reported-by: Michal Kubecek <mkubecek@xxxxxxx> Reported-by: Firo Yang <firo.yang@xxxxxxxx> Reviewed-by: Michal Kubecek <mkubecek@xxxxxxx> Link: https://lore.kernel.org/netdev/20191120083919.GH27852@xxxxxxxxxxxxxxx/ Signed-off-by: Jakub Kicinski <jakub.kicinski@xxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
