Starting from c4ad8f98bef7 "execve: use 'struct filename *' for executable name passing" bprm->filename can not go away after flush_old_exec(), so we do not need to save the binary name in bprm->tcomm[] added by 96e02d158678 "exec: fix use-after-free bug in setup_new_exec()".
And there was never need for filename_to_taskname-like code, we can simply do set_task_comm(kbasename(filename). This patch has to change set_task_comm() and trace_task_rename() to accept "const char *", but I think this change is also good. Signed-off-by: Oleg Nesterov <[email protected]> --- fs/exec.c | 21 ++------------------- include/linux/binfmts.h | 1 - include/linux/sched.h | 2 +- include/trace/events/task.h | 2 +- 4 files changed, 4 insertions(+), 22 deletions(-) diff --git a/fs/exec.c b/fs/exec.c index 3d78fcc..de5faec 100644 --- a/fs/exec.c +++ b/fs/exec.c @@ -1041,7 +1041,7 @@ EXPORT_SYMBOL_GPL(get_task_comm); * so that a new one can be started */ -void set_task_comm(struct task_struct *tsk, char *buf) +void set_task_comm(struct task_struct *tsk, const char *buf) { task_lock(tsk); trace_task_rename(tsk, buf); @@ -1050,21 +1050,6 @@ void set_task_comm(struct task_struct *tsk, char *buf) perf_event_comm(tsk); } -static void filename_to_taskname(char *tcomm, const char *fn, unsigned int len) -{ - int i, ch; - - /* Copies the binary name from after last slash */ - for (i = 0; (ch = *(fn++)) != '\0';) { - if (ch == '/') - i = 0; /* overwrite what we wrote */ - else - if (i < len - 1) - tcomm[i++] = ch; - } - tcomm[i] = '\0'; -} - int flush_old_exec(struct linux_binprm * bprm) { int retval; @@ -1078,8 +1063,6 @@ int flush_old_exec(struct linux_binprm * bprm) goto out; set_mm_exe_file(bprm->mm, bprm->file); - - filename_to_taskname(bprm->tcomm, bprm->filename, sizeof(bprm->tcomm)); /* * Release all of the old mmap stuff */ @@ -1122,7 +1105,7 @@ void setup_new_exec(struct linux_binprm * bprm) else set_dumpable(current->mm, suid_dumpable); - set_task_comm(current, bprm->tcomm); + set_task_comm(current, kbasename(bprm->filename)); /* Set the new mm task size. We have to do that late because it may * depend on TIF_32BIT which is only updated in flush_thread() on diff --git a/include/linux/binfmts.h b/include/linux/binfmts.h index b4a745d..61f29e5 100644 --- a/include/linux/binfmts.h +++ b/include/linux/binfmts.h @@ -44,7 +44,6 @@ struct linux_binprm { unsigned interp_flags; unsigned interp_data; unsigned long loader, exec; - char tcomm[TASK_COMM_LEN]; }; #define BINPRM_FLAGS_ENFORCE_NONDUMP_BIT 0 diff --git a/include/linux/sched.h b/include/linux/sched.h index af42ee2..7653285 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -2317,7 +2317,7 @@ extern long do_fork(unsigned long, unsigned long, unsigned long, int __user *, i struct task_struct *fork_idle(int); extern pid_t kernel_thread(int (*fn)(void *), void *arg, unsigned long flags); -extern void set_task_comm(struct task_struct *tsk, char *from); +extern void set_task_comm(struct task_struct *tsk, const char *from); extern char *get_task_comm(char *to, struct task_struct *tsk); #ifdef CONFIG_SMP diff --git a/include/trace/events/task.h b/include/trace/events/task.h index 102a646..dee3bb1 100644 --- a/include/trace/events/task.h +++ b/include/trace/events/task.h @@ -32,7 +32,7 @@ TRACE_EVENT(task_newtask, TRACE_EVENT(task_rename, - TP_PROTO(struct task_struct *task, char *comm), + TP_PROTO(struct task_struct *task, const char *comm), TP_ARGS(task, comm), -- 1.5.5.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
