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From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: stable@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	patches@lists.linux.dev, Edward Humes <aurxenon@lunos.org>,
	Matt Turner <mattst88@gmail.com>, Sasha Levin <sashal@kernel.org>
Subject: [PATCH 4.14 14/21] alpha: fix R_ALPHA_LITERAL reloc for large modules
Date: Wed, 15 Mar 2023 13:12:37 +0100	[thread overview]
Message-ID: <20230315115719.342047431@linuxfoundation.org> (raw)
In-Reply-To: <20230315115718.796692048@linuxfoundation.org>

From: Edward Humes <aurxenon@lunos.org>

[ Upstream commit b6b17a8b3ecd878d98d5472a9023ede9e669ca72 ]

Previously, R_ALPHA_LITERAL relocations would overflow for large kernel
modules.

This was because the Alpha's apply_relocate_add was relying on the kernel's
module loader to have sorted the GOT towards the very end of the module as it
was mapped into memory in order to correctly assign the global pointer. While
this behavior would mostly work fine for small kernel modules, this approach
would overflow on kernel modules with large GOT's since the global pointer
would be very far away from the GOT, and thus, certain entries would be out of
range.

This patch fixes this by instead using the Tru64 behavior of assigning the
global pointer to be 32KB away from the start of the GOT. The change made
in this patch won't work for multi-GOT kernel modules as it makes the
assumption the module only has one GOT located at the beginning of .got,
although for the vast majority kernel modules, this should be fine. Of the
kernel modules that would previously result in a relocation error, none of
them, even modules like nouveau, have even come close to filling up a single
GOT, and they've all worked fine under this patch.

Signed-off-by: Edward Humes <aurxenon@lunos.org>
Signed-off-by: Matt Turner <mattst88@gmail.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 arch/alpha/kernel/module.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/arch/alpha/kernel/module.c b/arch/alpha/kernel/module.c
index 47632fa8c24e0..b169dc9a9ac17 100644
--- a/arch/alpha/kernel/module.c
+++ b/arch/alpha/kernel/module.c
@@ -158,10 +158,8 @@ apply_relocate_add(Elf64_Shdr *sechdrs, const char *strtab,
 	base = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr;
 	symtab = (Elf64_Sym *)sechdrs[symindex].sh_addr;
 
-	/* The small sections were sorted to the end of the segment.
-	   The following should definitely cover them.  */
-	gp = (u64)me->core_layout.base + me->core_layout.size - 0x8000;
 	got = sechdrs[me->arch.gotsecindex].sh_addr;
+	gp = got + 0x8000;
 
 	for (i = 0; i < n; i++) {
 		unsigned long r_sym = ELF64_R_SYM (rela[i].r_info);
-- 
2.39.2




  parent reply	other threads:[~2023-03-15 12:14 UTC|newest]

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-03-15 12:12 [PATCH 4.14 00/21] 4.14.310-rc1 review Greg Kroah-Hartman
2023-03-15 12:12 ` [PATCH 4.14 01/21] fs: prevent out-of-bounds array speculation when closing a file descriptor Greg Kroah-Hartman
2023-03-15 12:12 ` [PATCH 4.14 02/21] x86/CPU/AMD: Disable XSAVES on AMD family 0x17 Greg Kroah-Hartman
2023-03-15 12:12 ` [PATCH 4.14 03/21] ext4: fix RENAME_WHITEOUT handling for inline directories Greg Kroah-Hartman
2023-03-15 12:12 ` [PATCH 4.14 04/21] ext4: fix another off-by-one fsmap error on 1k block filesystems Greg Kroah-Hartman
2023-03-15 12:12 ` [PATCH 4.14 05/21] ext4: move where set the MAY_INLINE_DATA flag is set Greg Kroah-Hartman
2023-03-15 12:12 ` [PATCH 4.14 06/21] ext4: fix WARNING in ext4_update_inline_data Greg Kroah-Hartman
2023-03-15 12:12 ` [PATCH 4.14 07/21] ext4: zero i_disksize when initializing the bootloader inode Greg Kroah-Hartman
2023-03-15 12:12 ` [PATCH 4.14 08/21] nfc: change order inside nfc_se_io error path Greg Kroah-Hartman
2023-03-15 12:12 ` [PATCH 4.14 09/21] nfc: fdp: add null check of devm_kmalloc_array in fdp_nci_i2c_read_device_properties Greg Kroah-Hartman
2023-03-15 12:12 ` [PATCH 4.14 10/21] ila: do not generate empty messages in ila_xlat_nl_cmd_get_mapping() Greg Kroah-Hartman
2023-03-15 12:12 ` [PATCH 4.14 11/21] net: caif: Fix use-after-free in cfusbl_device_notify() Greg Kroah-Hartman
2023-03-15 12:12 ` [PATCH 4.14 12/21] clk: qcom: mmcc-apq8084: remove spdm clocks Greg Kroah-Hartman
2023-03-15 12:12 ` [PATCH 4.14 13/21] MIPS: Fix a compilation issue Greg Kroah-Hartman
2023-03-15 12:12 ` Greg Kroah-Hartman [this message]
2023-03-15 12:12 ` [PATCH 4.14 15/21] macintosh: windfarm: Use unsigned type for 1-bit bitfields Greg Kroah-Hartman
2023-03-15 12:12 ` [PATCH 4.14 16/21] PCI: Add SolidRun vendor ID Greg Kroah-Hartman
2023-03-15 12:12 ` [PATCH 4.14 17/21] PCI: Avoid FLR for SolidRun SNET DPU rev 1 Greg Kroah-Hartman
2023-03-15 12:12 ` [PATCH 4.14 18/21] media: ov5640: Fix analogue gain control Greg Kroah-Hartman
2023-03-15 12:12 ` [PATCH 4.14 19/21] tipc: improve function tipc_wait_for_cond() Greg Kroah-Hartman
2023-03-15 12:12 ` [PATCH 4.14 20/21] drm/i915: Dont use BAR mappings for ring buffers with LLC Greg Kroah-Hartman
2023-03-15 12:12   ` [Intel-gfx] " Greg Kroah-Hartman
2023-03-15 12:12 ` [PATCH 4.14 21/21] x86/cpu: Fix LFENCE serialization check in init_amd() Greg Kroah-Hartman
2023-03-15 13:55 ` [PATCH 4.14 00/21] 4.14.310-rc1 review Chris Paterson

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