[IA64] fix file and descriptor handling in perfmon
Races galore... General rule: as soon as it's in descriptor table, it's over; another thread might have started IO on it/dup2() it elsewhere/dup2() something *over* it/etc. fd_install() is the very last step one should take - it's a point of no return. Besides, the damn thing leaked on failure exits... Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Tony Luck <tony.luck@intel.com>
This commit is contained in:
Al Viro
Tony Luck
parent
848376c774
commit
f8e811b989
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@ -867,7 +867,7 @@ pfm_rvfree(void *mem, unsigned long size)
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}
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static pfm_context_t *
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pfm_context_alloc(void)
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pfm_context_alloc(int ctx_flags)
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{
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pfm_context_t *ctx;
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@ -878,6 +878,46 @@ pfm_context_alloc(void)
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ctx = kzalloc(sizeof(pfm_context_t), GFP_KERNEL);
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if (ctx) {
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DPRINT(("alloc ctx @%p\n", ctx));
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/*
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* init context protection lock
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*/
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spin_lock_init(&ctx->ctx_lock);
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/*
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* context is unloaded
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*/
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ctx->ctx_state = PFM_CTX_UNLOADED;
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/*
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* initialization of context's flags
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*/
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ctx->ctx_fl_block = (ctx_flags & PFM_FL_NOTIFY_BLOCK) ? 1 : 0;
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ctx->ctx_fl_system = (ctx_flags & PFM_FL_SYSTEM_WIDE) ? 1: 0;
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ctx->ctx_fl_no_msg = (ctx_flags & PFM_FL_OVFL_NO_MSG) ? 1: 0;
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/*
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* will move to set properties
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* ctx->ctx_fl_excl_idle = (ctx_flags & PFM_FL_EXCL_IDLE) ? 1: 0;
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*/
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/*
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* init restart semaphore to locked
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*/
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init_completion(&ctx->ctx_restart_done);
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/*
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* activation is used in SMP only
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*/
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ctx->ctx_last_activation = PFM_INVALID_ACTIVATION;
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SET_LAST_CPU(ctx, -1);
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/*
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* initialize notification message queue
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*/
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ctx->ctx_msgq_head = ctx->ctx_msgq_tail = 0;
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init_waitqueue_head(&ctx->ctx_msgq_wait);
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init_waitqueue_head(&ctx->ctx_zombieq);
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}
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return ctx;
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}
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@ -2165,28 +2205,21 @@ static struct dentry_operations pfmfs_dentry_operations = {
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};
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static int
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pfm_alloc_fd(struct file **cfile)
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static struct file *
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pfm_alloc_file(pfm_context_t *ctx)
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{
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int fd, ret = 0;
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struct file *file = NULL;
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struct inode * inode;
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struct file *file;
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struct inode *inode;
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struct dentry *dentry;
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char name[32];
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struct qstr this;
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fd = get_unused_fd();
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if (fd < 0) return -ENFILE;
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ret = -ENFILE;
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file = get_empty_filp();
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if (!file) goto out;
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/*
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* allocate a new inode
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*/
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inode = new_inode(pfmfs_mnt->mnt_sb);
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if (!inode) goto out;
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if (!inode)
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return ERR_PTR(-ENOMEM);
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DPRINT(("new inode ino=%ld @%p\n", inode->i_ino, inode));
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@ -2199,59 +2232,28 @@ pfm_alloc_fd(struct file **cfile)
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this.len = strlen(name);
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this.hash = inode->i_ino;
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ret = -ENOMEM;
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/*
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* allocate a new dcache entry
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*/
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file->f_path.dentry = d_alloc(pfmfs_mnt->mnt_sb->s_root, &this);
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if (!file->f_path.dentry) goto out;
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dentry = d_alloc(pfmfs_mnt->mnt_sb->s_root, &this);
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if (!dentry) {
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iput(inode);
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return ERR_PTR(-ENOMEM);
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}
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file->f_path.dentry->d_op = &pfmfs_dentry_operations;
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dentry->d_op = &pfmfs_dentry_operations;
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d_add(dentry, inode);
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d_add(file->f_path.dentry, inode);
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file->f_path.mnt = mntget(pfmfs_mnt);
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file->f_mapping = inode->i_mapping;
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file = alloc_file(pfmfs_mnt, dentry, FMODE_READ, &pfm_file_ops);
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if (!file) {
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dput(dentry);
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return ERR_PTR(-ENFILE);
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}
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file->f_op = &pfm_file_ops;
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file->f_mode = FMODE_READ;
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file->f_flags = O_RDONLY;
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file->f_pos = 0;
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file->private_data = ctx;
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/*
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* may have to delay until context is attached?
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*/
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fd_install(fd, file);
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/*
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* the file structure we will use
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*/
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*cfile = file;
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return fd;
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out:
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if (file) put_filp(file);
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put_unused_fd(fd);
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return ret;
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}
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static void
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pfm_free_fd(int fd, struct file *file)
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{
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struct files_struct *files = current->files;
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struct fdtable *fdt;
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/*
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* there ie no fd_uninstall(), so we do it here
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*/
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spin_lock(&files->file_lock);
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fdt = files_fdtable(files);
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rcu_assign_pointer(fdt->fd[fd], NULL);
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spin_unlock(&files->file_lock);
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if (file)
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put_filp(file);
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put_unused_fd(fd);
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return file;
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}
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static int
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@ -2475,6 +2477,7 @@ pfm_setup_buffer_fmt(struct task_struct *task, struct file *filp, pfm_context_t
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/* link buffer format and context */
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ctx->ctx_buf_fmt = fmt;
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ctx->ctx_fl_is_sampling = 1; /* assume record() is defined */
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/*
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* check if buffer format wants to use perfmon buffer allocation/mapping service
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@ -2669,78 +2672,45 @@ pfm_context_create(pfm_context_t *ctx, void *arg, int count, struct pt_regs *reg
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{
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pfarg_context_t *req = (pfarg_context_t *)arg;
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struct file *filp;
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struct path path;
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int ctx_flags;
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int fd;
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int ret;
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/* let's check the arguments first */
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ret = pfarg_is_sane(current, req);
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if (ret < 0) return ret;
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if (ret < 0)
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return ret;
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ctx_flags = req->ctx_flags;
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ret = -ENOMEM;
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ctx = pfm_context_alloc();
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if (!ctx) goto error;
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fd = get_unused_fd();
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if (fd < 0)
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return fd;
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ret = pfm_alloc_fd(&filp);
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if (ret < 0) goto error_file;
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ctx = pfm_context_alloc(ctx_flags);
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if (!ctx)
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goto error;
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req->ctx_fd = ctx->ctx_fd = ret;
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filp = pfm_alloc_file(ctx);
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if (IS_ERR(filp)) {
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ret = PTR_ERR(filp);
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goto error_file;
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}
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/*
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* attach context to file
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*/
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filp->private_data = ctx;
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req->ctx_fd = ctx->ctx_fd = fd;
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/*
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* does the user want to sample?
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*/
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if (pfm_uuid_cmp(req->ctx_smpl_buf_id, pfm_null_uuid)) {
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ret = pfm_setup_buffer_fmt(current, filp, ctx, ctx_flags, 0, req);
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if (ret) goto buffer_error;
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if (ret)
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goto buffer_error;
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}
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/*
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* init context protection lock
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*/
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spin_lock_init(&ctx->ctx_lock);
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/*
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* context is unloaded
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*/
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ctx->ctx_state = PFM_CTX_UNLOADED;
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/*
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* initialization of context's flags
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*/
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ctx->ctx_fl_block = (ctx_flags & PFM_FL_NOTIFY_BLOCK) ? 1 : 0;
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ctx->ctx_fl_system = (ctx_flags & PFM_FL_SYSTEM_WIDE) ? 1: 0;
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ctx->ctx_fl_is_sampling = ctx->ctx_buf_fmt ? 1 : 0; /* assume record() is defined */
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ctx->ctx_fl_no_msg = (ctx_flags & PFM_FL_OVFL_NO_MSG) ? 1: 0;
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/*
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* will move to set properties
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* ctx->ctx_fl_excl_idle = (ctx_flags & PFM_FL_EXCL_IDLE) ? 1: 0;
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*/
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/*
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* init restart semaphore to locked
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*/
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init_completion(&ctx->ctx_restart_done);
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/*
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* activation is used in SMP only
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*/
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ctx->ctx_last_activation = PFM_INVALID_ACTIVATION;
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SET_LAST_CPU(ctx, -1);
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/*
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* initialize notification message queue
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*/
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ctx->ctx_msgq_head = ctx->ctx_msgq_tail = 0;
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init_waitqueue_head(&ctx->ctx_msgq_wait);
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init_waitqueue_head(&ctx->ctx_zombieq);
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DPRINT(("ctx=%p flags=0x%x system=%d notify_block=%d excl_idle=%d no_msg=%d ctx_fd=%d \n",
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ctx,
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ctx_flags,
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@ -2755,10 +2725,14 @@ pfm_context_create(pfm_context_t *ctx, void *arg, int count, struct pt_regs *reg
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*/
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pfm_reset_pmu_state(ctx);
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fd_install(fd, filp);
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return 0;
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buffer_error:
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pfm_free_fd(ctx->ctx_fd, filp);
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path = filp->f_path;
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put_filp(filp);
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path_put(&path);
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if (ctx->ctx_buf_fmt) {
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pfm_buf_fmt_exit(ctx->ctx_buf_fmt, current, NULL, regs);
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@ -2767,6 +2741,7 @@ error_file:
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pfm_context_free(ctx);
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error:
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put_unused_fd(fd);
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return ret;
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}
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