/* * Read/write thread of a guest agent for virtio-trace * * Copyright (C) 2012 Hitachi, Ltd. * Created by Yoshihiro Yunomae * Masami Hiramatsu * * Licensed under GPL version 2 only. * */ #define _GNU_SOURCE #include #include #include #include #include #include "trace-agent.h" #define READ_WAIT_USEC 100000 void *rw_thread_info_new(void) { struct rw_thread_info *rw_ti; rw_ti = zalloc(sizeof(struct rw_thread_info)); if (rw_ti == NULL) { pr_err("rw_thread_info zalloc error\n"); exit(EXIT_FAILURE); } rw_ti->cpu_num = -1; rw_ti->in_fd = -1; rw_ti->out_fd = -1; rw_ti->read_pipe = -1; rw_ti->write_pipe = -1; rw_ti->pipe_size = PIPE_INIT; return rw_ti; } void *rw_thread_init(int cpu, const char *in_path, const char *out_path, bool stdout_flag, unsigned long pipe_size, struct rw_thread_info *rw_ti) { int data_pipe[2]; rw_ti->cpu_num = cpu; /* set read(input) fd */ rw_ti->in_fd = open(in_path, O_RDONLY); if (rw_ti->in_fd == -1) { pr_err("Could not open in_fd (CPU:%d)\n", cpu); goto error; } /* set write(output) fd */ if (!stdout_flag) { /* virtio-serial output mode */ rw_ti->out_fd = open(out_path, O_WRONLY); if (rw_ti->out_fd == -1) { pr_err("Could not open out_fd (CPU:%d)\n", cpu); goto error; } } else /* stdout mode */ rw_ti->out_fd = STDOUT_FILENO; if (pipe2(data_pipe, O_NONBLOCK) < 0) { pr_err("Could not create pipe in rw-thread(%d)\n", cpu); goto error; } /* * Size of pipe is 64kB in default based on fs/pipe.c. * To read/write trace data speedy, pipe size is changed. */ if (fcntl(*data_pipe, F_SETPIPE_SZ, pipe_size) < 0) { pr_err("Could not change pipe size in rw-thread(%d)\n", cpu); goto error; } rw_ti->read_pipe = data_pipe[1]; rw_ti->write_pipe = data_pipe[0]; rw_ti->pipe_size = pipe_size; return NULL; error: exit(EXIT_FAILURE); } /* Bind a thread to a cpu */ static void bind_cpu(int cpu_num) { cpu_set_t mask; CPU_ZERO(&mask); CPU_SET(cpu_num, &mask); /* bind my thread to cpu_num by assigning zero to the first argument */ if (sched_setaffinity(0, sizeof(mask), &mask) == -1) pr_err("Could not set CPU#%d affinity\n", (int)cpu_num); } static void *rw_thread_main(void *thread_info) { ssize_t rlen, wlen; ssize_t ret; struct rw_thread_info *ts = (struct rw_thread_info *)thread_info; bind_cpu(ts->cpu_num); while (1) { /* Wait for a read order of trace data by Host OS */ if (!global_run_operation) { pthread_mutex_lock(&mutex_notify); pthread_cond_wait(&cond_wakeup, &mutex_notify); pthread_mutex_unlock(&mutex_notify); } if (global_sig_receive) break; /* * Each thread read trace_pipe_raw of each cpu bounding the * thread, so contention of multi-threads does not occur. */ rlen = splice(ts->in_fd, NULL, ts->read_pipe, NULL, ts->pipe_size, SPLICE_F_MOVE | SPLICE_F_MORE); if (rlen < 0) { pr_err("Splice_read in rw-thread(%d)\n", ts->cpu_num); goto error; } else if (rlen == 0) { /* * If trace data do not exist or are unreadable not * for exceeding the page size, splice_read returns * NULL. Then, this waits for being filled the data in a * ring-buffer. */ usleep(READ_WAIT_USEC); pr_debug("Read retry(cpu:%d)\n", ts->cpu_num); continue; } wlen = 0; do { ret = splice(ts->write_pipe, NULL, ts->out_fd, NULL, rlen - wlen, SPLICE_F_MOVE | SPLICE_F_MORE); if (ret < 0) { pr_err("Splice_write in rw-thread(%d)\n", ts->cpu_num); goto error; } else if (ret == 0) /* * When host reader is not in time for reading * trace data, guest will be stopped. This is * because char dev in QEMU is not supported * non-blocking mode. Then, writer might be * sleep in that case. * This sleep will be removed by supporting * non-blocking mode. */ sleep(1); wlen += ret; } while (wlen < rlen); } return NULL; error: exit(EXIT_FAILURE); } pthread_t rw_thread_run(struct rw_thread_info *rw_ti) { int ret; pthread_t rw_thread_per_cpu; ret = pthread_create(&rw_thread_per_cpu, NULL, rw_thread_main, rw_ti); if (ret != 0) { pr_err("Could not create a rw thread(%d)\n", rw_ti->cpu_num); exit(EXIT_FAILURE); } return rw_thread_per_cpu; } de:
authorLinus Torvalds <torvalds@linux-foundation.org>2017-01-29 13:50:06 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2017-01-29 13:50:06 -0800
commit39cb2c9a316e77f6dfba96c543e55b6672d5a37e (patch)
tree98fe974ee4e20121253de7f61fc8d01bdb3821c1 /include/dt-bindings/pinctrl/nomadik.h
parent2c5d9555d6d937966d79d4c6529a5f7b9206e405 (diff)
drm/i915: Check for NULL i915_vma in intel_unpin_fb_obj()
I've seen this trigger twice now, where the i915_gem_object_to_ggtt() call in intel_unpin_fb_obj() returns NULL, resulting in an oops immediately afterwards as the (inlined) call to i915_vma_unpin_fence() tries to dereference it. It seems to be some race condition where the object is going away at shutdown time, since both times happened when shutting down the X server. The call chains were different: - VT ioctl(KDSETMODE, KD_TEXT): intel_cleanup_plane_fb+0x5b/0xa0 [i915] drm_atomic_helper_cleanup_planes+0x6f/0x90 [drm_kms_helper] intel_atomic_commit_tail+0x749/0xfe0 [i915] intel_atomic_commit+0x3cb/0x4f0 [i915] drm_atomic_commit+0x4b/0x50 [drm] restore_fbdev_mode+0x14c/0x2a0 [drm_kms_helper] drm_fb_helper_restore_fbdev_mode_unlocked+0x34/0x80 [drm_kms_helper] drm_fb_helper_set_par+0x2d/0x60 [drm_kms_helper] intel_fbdev_set_par+0x18/0x70 [i915] fb_set_var+0x236/0x460 fbcon_blank+0x30f/0x350 do_unblank_screen+0xd2/0x1a0 vt_ioctl+0x507/0x12a0 tty_ioctl+0x355/0xc30 do_vfs_ioctl+0xa3/0x5e0 SyS_ioctl+0x79/0x90 entry_SYSCALL_64_fastpath+0x13/0x94 - i915 unpin_work workqueue: intel_unpin_work_fn+0x58/0x140 [i915] process_one_work+0x1f1/0x480 worker_thread+0x48/0x4d0 kthread+0x101/0x140 and this patch purely papers over the issue by adding a NULL pointer check and a WARN_ON_ONCE() to avoid the oops that would then generally make the machine unresponsive. Other callers of i915_gem_object_to_ggtt() seem to also check for the returned pointer being NULL and warn about it, so this clearly has happened before in other places. [ Reported it originally to the i915 developers on Jan 8, applying the ugly workaround on my own now after triggering the problem for the second time with no feedback. This is likely to be the same bug reported as https://bugs.freedesktop.org/show_bug.cgi?id=98829 https://bugs.freedesktop.org/show_bug.cgi?id=99134 which has a patch for the underlying problem, but it hasn't gotten to me, so I'm applying the workaround. ] Cc: Daniel Vetter <daniel.vetter@intel.com> Cc: Jani Nikula <jani.nikula@linux.intel.com> Cc: Ville Syrjälä <ville.syrjala@linux.intel.com> Cc: Chris Wilson <chris@chris-wilson.co.uk> Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com> Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com> Cc: Imre Deak <imre.deak@intel.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include/dt-bindings/pinctrl/nomadik.h')