(CC: davem, soheil & gregkh)

On 03/17/18 20:12, Holger Hoffstätte wrote:

On 03/17/18 19:41, Carlos Carvalho wrote:

...

I've put 4.14.27 this morning in this machine and in about 2h it started showing null dereferences identical to the following one. There were several of them, with about 1/2h of interval. Strangely it continued to work and I saw no other anomalies. I've just reverted to 4.14.26.

It only happened in this machine, which has a net traffic of several Gb/s and thousands of simultaneous connections.

Mar 17 13:29:21 sagres kernel: : BUG: unable to handle kernel NULL pointer dereference at 0000000000000038 Mar 17 13:29:21 sagres kernel: : IP: tcp_push+0x4e/0xe7 Mar 17 13:29:21 sagres kernel: : PGD 0 P4D 0 Mar 17 13:29:21 sagres kernel: : Oops: 0002 [#1] SMP PTI Mar 17 13:29:21 sagres kernel: : CPU: 55 PID: 2658 Comm: apache2 Not tainted 4.14.27 #4

(snip)

Fixed by: https://www.spinics.net/lists/netdev/msg489445.html

-h

This patch is in the netdev patchwork at https://patchwork.ozlabs.org/patch/886324/ but has been marked as "not applicable" without further queued/rejected comment from Dave, so I believe it became a victim of email lossage. As the patch says it doesn't apply to anything older than 4.14, but it has been tested & reported by several people as fixing the problem, and indeed works fine. Since GregKH only accepts net patches from Dave I wanted to make sure it got queued up for 4.14.

Thanks, Holger