the bitrig pedro_bwrite branch has been created by pedro. it is 0 commits behind master, and 1 commit ahead.
commit d06783b09b54ebd7e9965f988c44f83c2f4be77c diff: https://github.com/bitrig/bitrig/commit/d06783b author: pedro martelletto <[email protected]> date: Thu Jan 1 13:50:36 2015 +0100 fix race condition in bwrite() in bwrite(), don't inspect b_bq after calling VOP_STRATEGY() and lowering the IPL. at that point we no longer own the buffer, so it is possible for the issued i/o to complete between the moment we check if b_bq is set and the subsequent call to bufq_wait(), leading to a null pointer dereference in the latter function, as observed empirically this morning on my amd64 running dpb -p 8. M sys/kern/kern_bufq.c M sys/kern/vfs_bio.c M sys/sys/buf.h
