/* * linux/net/sunrpc/socklib.c * * Common socket helper routines for RPC client and server * * Copyright (C) 1995, 1996 Olaf Kirch */ #include #include #include #include #include #include #include #include #include /** * xdr_skb_read_bits - copy some data bits from skb to internal buffer * @desc: sk_buff copy helper * @to: copy destination * @len: number of bytes to copy * * Possibly called several times to iterate over an sk_buff and copy * data out of it. */ size_t xdr_skb_read_bits(struct xdr_skb_reader *desc, void *to, size_t len) { if (len > desc->count) len = desc->count; if (unlikely(skb_copy_bits(desc->skb, desc->offset, to, len))) return 0; desc->count -= len; desc->offset += len; return len; } EXPORT_SYMBOL_GPL(xdr_skb_read_bits); /** * xdr_skb_read_and_csum_bits - copy and checksum from skb to buffer * @desc: sk_buff copy helper * @to: copy destination * @len: number of bytes to copy * * Same as skb_read_bits, but calculate a checksum at the same time. */ static size_t xdr_skb_read_and_csum_bits(struct xdr_skb_reader *desc, void *to, size_t len) { unsigned int pos; __wsum csum2; if (len > desc->count) len = desc->count; pos = desc->offset; csum2 = skb_copy_and_csum_bits(desc->skb, pos, to, len, 0); desc->csum = csum_block_add(desc->csum, csum2, pos); desc->count -= len; desc->offset += len; return len; } /** * xdr_partial_copy_from_skb - copy data out of an skb * @xdr: target XDR buffer * @base: starting offset * @desc: sk_buff copy helper * @copy_actor: virtual method for copying data * */ ssize_t xdr_partial_copy_from_skb(struct xdr_buf *xdr, unsigned int base, struct xdr_skb_reader *desc, xdr_skb_read_actor copy_actor) { struct page **ppage = xdr->pages; unsigned int len, pglen = xdr->page_len; ssize_t copied = 0; size_t ret; len = xdr->head[0].iov_len; if (base < len) { len -= base; ret = copy_actor(desc, (char *)xdr->head[0].iov_base + base, len); copied += ret; if (ret != len || !desc->count) goto out; base = 0; } else base -= len; if (unlikely(pglen == 0)) goto copy_tail; if (unlikely(base >= pglen)) { base -= pglen; goto copy_tail; } if (base || xdr->page_base) { pglen -= base; base += xdr->page_base; ppage += base >> PAGE_SHIFT; base &= ~PAGE_MASK; } do { char *kaddr; /* ACL likes to be lazy in allocating pages - ACLs * are small by default but can get huge. */ if (unlikely(*ppage == NULL)) { *ppage = alloc_page(GFP_ATOMIC); if (unlikely(*ppage == NULL)) { if (copied == 0) copied = -ENOMEM; goto out; } } len = PAGE_SIZE; kaddr = kmap_atomic(*ppage); if (base) { len -= base; if (pglen < len) len = pglen; ret = copy_actor(desc, kaddr + base, len); base = 0; } else { if (pglen < len) len = pglen; ret = copy_actor(desc, kaddr, len); } flush_dcache_page(*ppage); kunmap_atomic(kaddr); copied += ret; if (ret != len || !desc->count) goto out; ppage++; } while ((pglen -= len) != 0); copy_tail: len = xdr->tail[0].iov_len; if (base < len) copied += copy_actor(desc, (char *)xdr->tail[0].iov_base + base, len - base); out: return copied; } EXPORT_SYMBOL_GPL(xdr_partial_copy_from_skb); /** * csum_partial_copy_to_xdr - checksum and copy data * @xdr: target XDR buffer * @skb: source skb * * We have set things up such that we perform the checksum of the UDP * packet in parallel with the copies into the RPC client iovec. -DaveM */ int csum_partial_copy_to_xdr(struct xdr_buf *xdr, struct sk_buff *skb) { struct xdr_skb_reader desc; desc.skb = skb; desc.offset = 0; desc.count = skb->len - desc.offset; if (skb_csum_unnecessary(skb)) goto no_checksum; desc.csum = csum_partial(skb->data, desc.offset, skb->csum); if (xdr_partial_copy_from_skb(xdr, 0, &desc, xdr_skb_read_and_csum_bits) < 0) return -1; if (desc.offset != skb->len) { __wsum csum2; csum2 = skb_checksum(skb, desc.offset, skb->len - desc.offset, 0); desc.csum = csum_block_add(desc.csum, csum2, desc.offset); } if (desc.count) return -1; if (csum_fold(desc.csum)) return -1; if (unlikely(skb->ip_summed == CHECKSUM_COMPLETE) && !skb->csum_complete_sw) netdev_rx_csum_fault(skb->dev); return 0; no_checksum: if (xdr_partial_copy_from_skb(xdr, 0, &desc, xdr_skb_read_bits) < 0) return -1; if (desc.count) return -1; return 0; } EXPORT_SYMBOL_GPL(csum_partial_copy_to_xdr); dt' onchange='this.form.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/tipc/netlink_compat.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/tipc/netlink_compat.c')