forked from luck/tmp_suning_uos_patched
b3f2d07f46
The use of ACCESS_ONCE() looks like a micro-optimization to force gcc to use
an indexed load for the register address, but it has an absolutely detrimental
effect on builds with gcc-5 and CONFIG_KASAN=y, leading to a very likely
kernel stack overflow aside from very complex object code:
hisilicon/hns/hns_dsaf_gmac.c: In function 'hns_gmac_update_stats':
hisilicon/hns/hns_dsaf_gmac.c:419:1: error: the frame size of 2912 bytes is larger than 1024 bytes [-Werror=frame-larger-than=]
hisilicon/hns/hns_dsaf_ppe.c: In function 'hns_ppe_reset_common':
hisilicon/hns/hns_dsaf_ppe.c:390:1: error: the frame size of 1184 bytes is larger than 1024 bytes [-Werror=frame-larger-than=]
hisilicon/hns/hns_dsaf_ppe.c: In function 'hns_ppe_get_regs':
hisilicon/hns/hns_dsaf_ppe.c:621:1: error: the frame size of 3632 bytes is larger than 1024 bytes [-Werror=frame-larger-than=]
hisilicon/hns/hns_dsaf_rcb.c: In function 'hns_rcb_get_common_regs':
hisilicon/hns/hns_dsaf_rcb.c:970:1: error: the frame size of 2784 bytes is larger than 1024 bytes [-Werror=frame-larger-than=]
hisilicon/hns/hns_dsaf_gmac.c: In function 'hns_gmac_get_regs':
hisilicon/hns/hns_dsaf_gmac.c:641:1: error: the frame size of 5728 bytes is larger than 1024 bytes [-Werror=frame-larger-than=]
hisilicon/hns/hns_dsaf_rcb.c: In function 'hns_rcb_get_ring_regs':
hisilicon/hns/hns_dsaf_rcb.c:1021:1: error: the frame size of 2208 bytes is larger than 1024 bytes [-Werror=frame-larger-than=]
hisilicon/hns/hns_dsaf_main.c: In function 'hns_dsaf_comm_init':
hisilicon/hns/hns_dsaf_main.c:1209:1: error: the frame size of 1904 bytes is larger than 1024 bytes [-Werror=frame-larger-than=]
hisilicon/hns/hns_dsaf_xgmac.c: In function 'hns_xgmac_get_regs':
hisilicon/hns/hns_dsaf_xgmac.c:748:1: error: the frame size of 4704 bytes is larger than 1024 bytes [-Werror=frame-larger-than=]
hisilicon/hns/hns_dsaf_main.c: In function 'hns_dsaf_update_stats':
hisilicon/hns/hns_dsaf_main.c:2420:1: error: the frame size of 1088 bytes is larger than 1024 bytes [-Werror=frame-larger-than=]
hisilicon/hns/hns_dsaf_main.c: In function 'hns_dsaf_get_regs':
hisilicon/hns/hns_dsaf_main.c:2753:1: error: the frame size of 10768 bytes is larger than 1024 bytes [-Werror=frame-larger-than=]
This does not seem to happen any more with gcc-7, but removing the ACCESS_ONCE
seems safe anyway and it avoids a serious issue for some people. I have verified
that with gcc-5.3.1, the object code we get is better in the new version
both with and without CONFIG_KASAN, as we no longer allocate a 1344 byte
stack frame for hns_dsaf_get_regs() but otherwise have practically identical
object code.
With gcc-7.0.0, removing ACCESS_ONCE has no effect, the object code is already
good either way.
This patch is probably not urgent to get into 4.11 as only KASAN=y builds
with certain compilers are affected, but I still think it makes sense to
backport into older kernels.
Cc: stable@vger.kernel.org
Fixes:
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|---|---|---|
| arch | ||
| block | ||
| certs | ||
| crypto | ||
| Documentation | ||
| drivers | ||
| firmware | ||
| fs | ||
| include | ||
| init | ||
| ipc | ||
| kernel | ||
| lib | ||
| mm | ||
| net | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .cocciconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| README | ||
Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. See Documentation/00-INDEX for a list of what is contained in each file. Please read the Documentation/process/changes.rst file, as it contains the requirements for building and running the kernel, and information about the problems which may result by upgrading your kernel.