From 8ac61436e6793deeba249d8e2b8332d60c83470f Mon Sep 17 00:00:00 2001 From: John Baldwin Date: Mon, 15 Mar 2004 18:48:28 +0000 Subject: [PATCH] Drop the proc lock around calls to the MD functions ptrace_single_step(), ptrace_set_pc(), and cpu_ptrace() so that those functions are free to acquire Giant, sleep, etc. We already do a PHOLD/PRELE around them so that it is safe to sleep inside of these routines if necessary. This allows ptrace() to be marked MP safe again as it no longer triggers lock order reversals on Alpha. Tested by: wilko --- sys/kern/sys_process.c | 17 +++++++++++------ sys/kern/syscalls.master | 2 +- 2 files changed, 12 insertions(+), 7 deletions(-) diff --git a/sys/kern/sys_process.c b/sys/kern/sys_process.c index 7a0c02ea01e..636d10bdba0 100644 --- a/sys/kern/sys_process.c +++ b/sys/kern/sys_process.c @@ -522,11 +522,13 @@ kern_ptrace(struct thread *td, int req, pid_t pid, void *addr, int data) switch (req) { case PT_STEP: + PROC_UNLOCK(p); error = ptrace_single_step(td2); if (error) { - _PRELE(p); - goto fail; + PRELE(p); + goto fail_noproc; } + PROC_LOCK(p); break; case PT_TO_SCE: p->p_stops |= S_PT_SCE; @@ -540,11 +542,13 @@ kern_ptrace(struct thread *td, int req, pid_t pid, void *addr, int data) } if (addr != (void *)1) { + PROC_UNLOCK(p); error = ptrace_set_pc(td2, (u_long)(uintfptr_t)addr); if (error) { - _PRELE(p); - goto fail; + PRELE(p); + goto fail_noproc; } + PROC_LOCK(p); } _PRELE(p); @@ -705,9 +709,9 @@ kern_ptrace(struct thread *td, int req, pid_t pid, void *addr, int data) #ifdef __HAVE_PTRACE_MACHDEP if (req >= PT_FIRSTMACH) { _PHOLD(p); - error = cpu_ptrace(td2, req, addr, data); - _PRELE(p); PROC_UNLOCK(p); + error = cpu_ptrace(td2, req, addr, data); + PRELE(p); return (error); } #endif @@ -719,6 +723,7 @@ kern_ptrace(struct thread *td, int req, pid_t pid, void *addr, int data) fail: PROC_UNLOCK(p); +fail_noproc: if (proctree_locked) sx_xunlock(&proctree_lock); return (error); diff --git a/sys/kern/syscalls.master b/sys/kern/syscalls.master index f23f05607a3..aa9c9696bba 100644 --- a/sys/kern/syscalls.master +++ b/sys/kern/syscalls.master @@ -76,7 +76,7 @@ 23 MSTD { int setuid(uid_t uid); } 24 MSTD { uid_t getuid(void); } 25 MSTD { uid_t geteuid(void); } -26 STD { int ptrace(int req, pid_t pid, caddr_t addr, int data); } +26 MSTD { int ptrace(int req, pid_t pid, caddr_t addr, int data); } 27 MSTD { int recvmsg(int s, struct msghdr *msg, int flags); } 28 MSTD { int sendmsg(int s, struct msghdr *msg, int flags); } 29 MSTD { int recvfrom(int s, caddr_t buf, size_t len, int flags, \