The branch main has been updated by trasz: URL: https://cgit.FreeBSD.org/src/commit/?id=8bbc0600cc21bbfdc3b8e67199eec4220952b7e3
commit 8bbc0600cc21bbfdc3b8e67199eec4220952b7e3 Author: Edward Tomasz Napierala <[email protected]> AuthorDate: 2021-10-30 08:53:55 +0000 Commit: Edward Tomasz Napierala <[email protected]> CommitDate: 2021-10-30 08:54:17 +0000 linux: Add additional ptracestop only if the debugger is Linux In 6e66030c4c0, additional ptracestop was added in order to implement PTRACE_EVENT_EXEC. Make it only apply to cases where the debugger is a Linux processes; native FreeBSD debuggers can trace Linux processes too, but they don't expect that additonal ptracestop. Fixes: 6e66030c4c0 Reported By: kib Reviewed By: kib Sponsored By: EPSRC Differential Revision: https://reviews.freebsd.org/D32726 --- sys/kern/subr_syscall.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) diff --git a/sys/kern/subr_syscall.c b/sys/kern/subr_syscall.c index fab67a68b0a3..dacd82f4c466 100644 --- a/sys/kern/subr_syscall.c +++ b/sys/kern/subr_syscall.c @@ -260,9 +260,15 @@ syscallret(struct thread *td) * the exec event now and then clear TDB_EXEC so that * the next stop is reported as a syscall exit by * linux_ptrace_status(). + * + * We are accessing p->p_pptr without any additional + * locks here: it cannot change while p is kept locked; + * while the debugger could in theory change its ABI + * while tracing another process, the outcome of such + * a race wouln't be deterministic anyway. */ - if ((td->td_dbgflags & TDB_EXEC) != 0 && - SV_PROC_ABI(td->td_proc) == SV_ABI_LINUX) { + if (traced && (td->td_dbgflags & TDB_EXEC) != 0 && + SV_PROC_ABI(p->p_pptr) == SV_ABI_LINUX) { ptracestop(td, SIGTRAP, NULL); td->td_dbgflags &= ~TDB_EXEC; }
