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d2a02e3c8b
blake2s_compress_generic is weakly aliased by blake2s_compress. The
current harness for function selection uses a function pointer, which is
ordinarily inlined and resolved at compile time. But when Clang's CFI is
enabled, CFI still triggers when making an indirect call via a weak
symbol. This seems like a bug in Clang's CFI, as though it's bucketing
weak symbols and strong symbols differently. It also only seems to
trigger when "full LTO" mode is used, rather than "thin LTO".
[ 0.000000][ T0] Kernel panic - not syncing: CFI failure (target: blake2s_compress_generic+0x0/0x1444)
[ 0.000000][ T0] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.16.0-mainline-06981-g076c855b846e #1
[ 0.000000][ T0] Hardware name: MT6873 (DT)
[ 0.000000][ T0] Call trace:
[ 0.000000][ T0] dump_backtrace+0xfc/0x1dc
[ 0.000000][ T0] dump_stack_lvl+0xa8/0x11c
[ 0.000000][ T0] panic+0x194/0x464
[ 0.000000][ T0] __cfi_check_fail+0x54/0x58
[ 0.000000][ T0] __cfi_slowpath_diag+0x354/0x4b0
[ 0.000000][ T0] blake2s_update+0x14c/0x178
[ 0.000000][ T0] _extract_entropy+0xf4/0x29c
[ 0.000000][ T0] crng_initialize_primary+0x24/0x94
[ 0.000000][ T0] rand_initialize+0x2c/0x6c
[ 0.000000][ T0] start_kernel+0x2f8/0x65c
[ 0.000000][ T0] __primary_switched+0xc4/0x7be4
[ 0.000000][ T0] Rebooting in 5 seconds..
Nonetheless, the function pointer method isn't so terrific anyway, so
this patch replaces it with a simple boolean, which also gets inlined
away. This successfully works around the Clang bug.
In general, I'm not too keen on all of the indirection involved here; it
clearly does more harm than good. Hopefully the whole thing can get
cleaned up down the road when lib/crypto is overhauled more
comprehensively. But for now, we go with a simple bandaid.
Fixes:
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|---|---|---|
| .. | ||
| boot | ||
| common | ||
| configs | ||
| crypto | ||
| include | ||
| kernel | ||
| lib | ||
| mach-actions | ||
| mach-alpine | ||
| mach-artpec | ||
| mach-asm9260 | ||
| mach-aspeed | ||
| mach-at91 | ||
| mach-axxia | ||
| mach-bcm | ||
| mach-berlin | ||
| mach-clps711x | ||
| mach-cns3xxx | ||
| mach-davinci | ||
| mach-digicolor | ||
| mach-dove | ||
| mach-ep93xx | ||
| mach-exynos | ||
| mach-footbridge | ||
| mach-gemini | ||
| mach-highbank | ||
| mach-hisi | ||
| mach-imx | ||
| mach-integrator | ||
| mach-iop32x | ||
| mach-ixp4xx | ||
| mach-keystone | ||
| mach-lpc18xx | ||
| mach-lpc32xx | ||
| mach-mediatek | ||
| mach-meson | ||
| mach-milbeaut | ||
| mach-mmp | ||
| mach-moxart | ||
| mach-mstar | ||
| mach-mv78xx0 | ||
| mach-mvebu | ||
| mach-mxs | ||
| mach-nomadik | ||
| mach-npcm | ||
| mach-nspire | ||
| mach-omap1 | ||
| mach-omap2 | ||
| mach-orion5x | ||
| mach-oxnas | ||
| mach-pxa | ||
| mach-qcom | ||
| mach-rda | ||
| mach-realtek | ||
| mach-realview | ||
| mach-rockchip | ||
| mach-rpc | ||
| mach-s3c | ||
| mach-s5pv210 | ||
| mach-sa1100 | ||
| mach-shmobile | ||
| mach-socfpga | ||
| mach-spear | ||
| mach-sti | ||
| mach-stm32 | ||
| mach-sunxi | ||
| mach-tegra | ||
| mach-uniphier | ||
| mach-ux500 | ||
| mach-versatile | ||
| mach-vexpress | ||
| mach-vt8500 | ||
| mach-zynq | ||
| mm | ||
| net | ||
| nwfpe | ||
| plat-omap | ||
| plat-orion | ||
| plat-pxa | ||
| plat-versatile | ||
| probes | ||
| tools | ||
| vdso | ||
| vfp | ||
| xen | ||
| Kbuild | ||
| Kconfig | ||
| Kconfig-nommu | ||
| Kconfig.assembler | ||
| Kconfig.debug | ||
| Makefile | ||