/* * CAIF Framing Layer. * * Copyright (C) ST-Ericsson AB 2010 * Author: Sjur Brendeland * License terms: GNU General Public License (GPL) version 2 */ #define pr_fmt(fmt) KBUILD_MODNAME ":%s(): " fmt, __func__ #include #include #include #include #include #include #include #include #define container_obj(layr) container_of(layr, struct cffrml, layer) struct cffrml { struct cflayer layer; bool dofcs; /* !< FCS active */ int __percpu *pcpu_refcnt; }; static int cffrml_receive(struct cflayer *layr, struct cfpkt *pkt); static int cffrml_transmit(struct cflayer *layr, struct cfpkt *pkt); static void cffrml_ctrlcmd(struct cflayer *layr, enum caif_ctrlcmd ctrl, int phyid); static u32 cffrml_rcv_error; static u32 cffrml_rcv_checsum_error; struct cflayer *cffrml_create(u16 phyid, bool use_fcs) { struct cffrml *this = kzalloc(sizeof(struct cffrml), GFP_ATOMIC); if (!this) return NULL; this->pcpu_refcnt = alloc_percpu(int); if (this->pcpu_refcnt == NULL) { kfree(this); return NULL; } caif_assert(offsetof(struct cffrml, layer) == 0); this->layer.receive = cffrml_receive; this->layer.transmit = cffrml_transmit; this->layer.ctrlcmd = cffrml_ctrlcmd; snprintf(this->layer.name, CAIF_LAYER_NAME_SZ, "frm%d", phyid); this->dofcs = use_fcs; this->layer.id = phyid; return (struct cflayer *) this; } void cffrml_free(struct cflayer *layer) { struct cffrml *this = container_obj(layer); free_percpu(this->pcpu_refcnt); kfree(layer); } void cffrml_set_uplayer(struct cflayer *this, struct cflayer *up) { this->up = up; } void cffrml_set_dnlayer(struct cflayer *this, struct cflayer *dn) { this->dn = dn; } static u16 cffrml_checksum(u16 chks, void *buf, u16 len) { /* FIXME: FCS should be moved to glue in order to use OS-Specific * solutions */ return crc_ccitt(chks, buf, len); } static int cffrml_receive(struct cflayer *layr, struct cfpkt *pkt) { u16 tmp; u16 len; u16 hdrchks; int pktchks; struct cffrml *this; this = container_obj(layr); cfpkt_extr_head(pkt, &tmp, 2); len = le16_to_cpu(tmp); /* Subtract for FCS on length if FCS is not used. */ if (!this->dofcs) len -= 2; if (cfpkt_setlen(pkt, len) < 0) { ++cffrml_rcv_error; pr_err("Framing length error (%d)\n", len); cfpkt_destroy(pkt); return -EPROTO; } /* * Don't do extract if FCS is false, rather do setlen - then we don't * get a cache-miss. */ if (this->dofcs) { cfpkt_extr_trail(pkt, &tmp, 2); hdrchks = le16_to_cpu(tmp); pktchks = cfpkt_iterate(pkt, cffrml_checksum, 0xffff); if (pktchks != hdrchks) { cfpkt_add_trail(pkt, &tmp, 2); ++cffrml_rcv_error; ++cffrml_rcv_checsum_error; pr_info("Frame checksum error (0x%x != 0x%x)\n", hdrchks, pktchks); return -EILSEQ; } } if (cfpkt_erroneous(pkt)) { ++cffrml_rcv_error; pr_err("Packet is erroneous!\n"); cfpkt_destroy(pkt); return -EPROTO; } if (layr->up == NULL) { pr_err("Layr up is missing!\n"); cfpkt_destroy(pkt); return -EINVAL; } return layr->up->receive(layr->up, pkt); } static int cffrml_transmit(struct cflayer *layr, struct cfpkt *pkt) { u16 chks; u16 len; __le16 data; struct cffrml *this = container_obj(layr); if (this->dofcs) { chks = cfpkt_iterate(pkt, cffrml_checksum, 0xffff); data = cpu_to_le16(chks); cfpkt_add_trail(pkt, &data, 2); } else { cfpkt_pad_trail(pkt, 2); } len = cfpkt_getlen(pkt); data = cpu_to_le16(len); cfpkt_add_head(pkt, &data, 2); cfpkt_info(pkt)->hdr_len += 2; if (cfpkt_erroneous(pkt)) { pr_err("Packet is erroneous!\n"); cfpkt_destroy(pkt); return -EPROTO; } if (layr->dn == NULL) { cfpkt_destroy(pkt); return -ENODEV; } return layr->dn->transmit(layr->dn, pkt); } static void cffrml_ctrlcmd(struct cflayer *layr, enum caif_ctrlcmd ctrl, int phyid) { if (layr->up && layr->up->ctrlcmd) layr->up->ctrlcmd(layr->up, ctrl, layr->id); } void cffrml_put(struct cflayer *layr) { struct cffrml *this = container_obj(layr); if (layr != NULL && this->pcpu_refcnt != NULL) this_cpu_dec(*this->pcpu_refcnt); } void cffrml_hold(struct cflayer *layr) { struct cffrml *this = container_obj(layr); if (layr != NULL && this->pcpu_refcnt != NULL) this_cpu_inc(*this->pcpu_refcnt); } int cffrml_refcnt_read(struct cflayer *layr) { int i, refcnt = 0; struct cffrml *this = container_obj(layr); for_each_possible_cpu(i) refcnt += *per_cpu_ptr(this->pcpu_refcnt, i); return refcnt; } m.submit();'>
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 /net/netlink/diag.c
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 'net/netlink/diag.c')