/* * dccp_probe - Observe the DCCP flow with kprobes. * * The idea for this came from Werner Almesberger's umlsim * Copyright (C) 2004, Stephen Hemminger * * Modified for DCCP from Stephen Hemminger's code * Copyright (C) 2006, Ian McDonald * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */ #include #include #include #include #include #include #include #include #include #include #include #include "dccp.h" #include "ccid.h" #include "ccids/ccid3.h" static int port; static int bufsize = 64 * 1024; static const char procname[] = "dccpprobe"; static struct { struct kfifo fifo; spinlock_t lock; wait_queue_head_t wait; struct timespec64 tstart; } dccpw; static void printl(const char *fmt, ...) { va_list args; int len; struct timespec64 now; char tbuf[256]; va_start(args, fmt); getnstimeofday64(&now); now = timespec64_sub(now, dccpw.tstart); len = sprintf(tbuf, "%lu.%06lu ", (unsigned long) now.tv_sec, (unsigned long) now.tv_nsec / NSEC_PER_USEC); len += vscnprintf(tbuf+len, sizeof(tbuf)-len, fmt, args); va_end(args); kfifo_in_locked(&dccpw.fifo, tbuf, len, &dccpw.lock); wake_up(&dccpw.wait); } static int jdccp_sendmsg(struct sock *sk, struct msghdr *msg, size_t size) { const struct inet_sock *inet = inet_sk(sk); struct ccid3_hc_tx_sock *hc = NULL; if (ccid_get_current_tx_ccid(dccp_sk(sk)) == DCCPC_CCID3) hc = ccid3_hc_tx_sk(sk); if (port == 0 || ntohs(inet->inet_dport) == port || ntohs(inet->inet_sport) == port) { if (hc) printl("%pI4:%u %pI4:%u %d %d %d %d %u %llu %llu %d\n", &inet->inet_saddr, ntohs(inet->inet_sport), &inet->inet_daddr, ntohs(inet->inet_dport), size, hc->tx_s, hc->tx_rtt, hc->tx_p, hc->tx_x_calc, hc->tx_x_recv >> 6, hc->tx_x >> 6, hc->tx_t_ipi); else printl("%pI4:%u %pI4:%u %d\n", &inet->inet_saddr, ntohs(inet->inet_sport), &inet->inet_daddr, ntohs(inet->inet_dport), size); } jprobe_return(); return 0; } static struct jprobe dccp_send_probe = { .kp = { .symbol_name = "dccp_sendmsg", }, .entry = jdccp_sendmsg, }; static int dccpprobe_open(struct inode *inode, struct file *file) { kfifo_reset(&dccpw.fifo); getnstimeofday64(&dccpw.tstart); return 0; } static ssize_t dccpprobe_read(struct file *file, char __user *buf, size_t len, loff_t *ppos) { int error = 0, cnt = 0; unsigned char *tbuf; if (!buf) return -EINVAL; if (len == 0) return 0; tbuf = vmalloc(len); if (!tbuf) return -ENOMEM; error = wait_event_interruptible(dccpw.wait, kfifo_len(&dccpw.fifo) != 0); if (error) goto out_free; cnt = kfifo_out_locked(&dccpw.fifo, tbuf, len, &dccpw.lock); error = copy_to_user(buf, tbuf, cnt) ? -EFAULT : 0; out_free: vfree(tbuf); return error ? error : cnt; } static const struct file_operations dccpprobe_fops = { .owner = THIS_MODULE, .open = dccpprobe_open, .read = dccpprobe_read, .llseek = noop_llseek, }; static __init int dccpprobe_init(void) { int ret = -ENOMEM; init_waitqueue_head(&dccpw.wait); spin_lock_init(&dccpw.lock); if (kfifo_alloc(&dccpw.fifo, bufsize, GFP_KERNEL)) return ret; if (!proc_create(procname, S_IRUSR, init_net.proc_net, &dccpprobe_fops)) goto err0; ret = register_jprobe(&dccp_send_probe); if (ret) { ret = request_module("dccp"); if (!ret) ret = register_jprobe(&dccp_send_probe); } if (ret) goto err1; pr_info("DCCP watch registered (port=%d)\n", port); return 0; err1: remove_proc_entry(procname, init_net.proc_net); err0: kfifo_free(&dccpw.fifo); return ret; } module_init(dccpprobe_init); static __exit void dccpprobe_exit(void) { kfifo_free(&dccpw.fifo); remove_proc_entry(procname, init_net.proc_net); unregister_jprobe(&dccp_send_probe); } module_exit(dccpprobe_exit); MODULE_PARM_DESC(port, "Port to match (0=all)"); module_param(port, int, 0); MODULE_PARM_DESC(bufsize, "Log buffer size (default 64k)"); module_param(bufsize, int, 0); MODULE_AUTHOR("Ian McDonald "); MODULE_DESCRIPTION("DCCP snooper"); MODULE_LICENSE("GPL"); r>commit39cb2c9a316e77f6dfba96c543e55b6672d5a37e (patch) tree98fe974ee4e20121253de7f61fc8d01bdb3821c1 /include/uapi/drm/qxl_drm.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/uapi/drm/qxl_drm.h')