[linux-yocto] [PATCH] modules: always page-align module section allocations
zhe.he at windriver.com
zhe.he at windriver.com
Fri Aug 16 09:01:05 PDT 2019
在 2019年8月16日 23:29，Paul Gortmaker <paul.gortmaker at windriver.com> 写下:
>
> [[linux-yocto] [PATCH] modules: always page-align module section allocations] On 16/08/2019 (Fri 15:36) zhe.he at windriver.com wrote:
>
> It helps maintainers if the version is embedded in the subject, like:
>
> [PATCH v4.18] modules: always page-align module section....
>
> > From: Jessica Yu <jeyu at kernel.org>
> >
> > Some arches (e.g., arm64, x86) have moved towards non-executable
> > module_alloc() allocations for security hardening reasons. That means
> > that the module loader will need to set the text section of a module to
> > executable, regardless of whether or not CONFIG_STRICT_MODULE_RWX is set.
> >
> > When CONFIG_STRICT_MODULE_RWX=y, module section allocations are always
> > page-aligned to handle memory rwx permissions. On some arches with
> > CONFIG_STRICT_MODULE_RWX=n however, when setting the module text to
> > executable, the BUG_ON() in frob_text() gets triggered since module
> > section allocations are not page-aligned when CONFIG_STRICT_MODULE_RWX=n.
> > Since the set_memory_* API works with pages, and since we need to call
> > set_memory_x() regardless of whether CONFIG_STRICT_MODULE_RWX is set, we
> > might as well page-align all module section allocations for ease of
> > managing rwx permissions of module sections (text, rodata, etc).
> >
> > Fixes: 2eef1399a866 ("modules: fix BUG when load module with rodata=n")
> > Reported-by: Martin Kaiser <lists at kaiser.cx>
> > Reported-by: Bartosz Golaszewski <brgl at bgdev.pl>
> > Tested-by: David Lechner <david at lechnology.com>
> > Tested-by: Martin Kaiser <martin at kaiser.cx>
> > Tested-by: Bartosz Golaszewski <bgolaszewski at baylibre.com>
> > Signed-off-by: Jessica Yu <jeyu at kernel.org>
> >
> > commit 38f054d549a869f22a02224cd276a27bf14b6171 upstream
>
> Normally we put this right at the top of the long log. Also this commit
> ID appears bogus - it does not exist in mainline.
Yes, it's from modules-next,
https://git.kernel.org/pub/scm/linux/kernel/git/jeyu/linux.git/commit/?h=modules-next
I can't wait as It blocks something.
>
> Also it seems very odd that the block of Signed-off lines are stuck in
> the middle of the long log.
>
> >
> > When loading modules with CONFIG_ARCH_HAS_STRICT_MODULE_RWX enabled and
> > CONFIG_STRICT_MODULE_RWX disabled, the memory allocated for modules would
> > not be page-aligned and cause the following BUG during frob_text.
> >
> > ------------[ cut here ]------------
> > kernel BUG at kernel/module.c:1907!
> > Internal error: Oops - BUG: 0 [#1] ARM
> > Modules linked in:
> > CPU: 0 PID: 89 Comm: systemd-modules Not tainted 5.3.0-rc2 #1
> > Hardware name: ARM-Versatile (Device Tree Support)
> > PC is at frob_text.constprop.0+0x2c/0x40
> > LR is at load_module+0x14b4/0x1d28
> > pc : [<c0082930>] lr : [<c0084bb0>] psr: 20000013
> > sp : ce44fe58 ip : 00000000 fp : 00000000
> > r10: 00000000 r9 : ce44feb8 r8 : 00000000
> > r7 : 00000001 r6 : bf00032c r5 : ce44ff40 r4 : bf000320
> > r3 : bf000400 r2 : 00000fff r1 : 00000220 r0 : bf000000
> > Flags: nzCv IRQs on FIQs on Mode SVC_32 ISA ARM Segment none
> > Control: 00093177 Table: 0e4c0000 DAC: 00000051
> > Process systemd-modules (pid: 89, stack limit = 0x9fccc8dc)
> > Stack: (0xce44fe58 to 0xce450000)
> > fe40: 00000000 cf1b05b8
> > fe60: 00000001 ce47cf08 bf002754 c07ae5d8 d0a2a484 bf002060 bf0004f8 00000000
> > fe80: b6d17910 c017cf1c ce47cf00 d0a29000 ce47cf00 ce44ff34 000014fc 00000000
> > fea0: 00000000 00000000 bf00025c 00000001 00000000 00000000 6e72656b 00006c65
> > fec0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
> > fee0: 00000000 00000000 00000000 00000000 00000000 c0ac9048 7fffffff 00000000
> > ff00: b6d17910 00000005 0000017b c0009208 ce44e000 00000000 b6ebfe54 c008562c
> > ff20: 7fffffff 00000000 00000003 cefd28f8 00000001 d0a29000 000014fc 00000000
> > ff40: d0a292cb d0a29380 d0a29000 000014fc d0a29f0c d0a29d90 d0a29a60 00000520
> > ff60: 00000710 00000718 00000826 00000000 00000000 00000000 00000708 00000023
> > ff80: 00000024 0000001c 00000000 00000016 00000000 c0ac9048 0041c620 00000000
> > ffa0: 00000000 c0009000 0041c620 00000000 00000005 b6d17910 00000000 00000000
> > ffc0: 0041c620 00000000 00000000 0000017b 0041f078 00000000 004098b0 b6ebfe54
> > ffe0: bedb6bc8 bedb6bb8 b6d0f91c b6c945a0 60000010 00000005 00000000 00000000
> > [<c0082930>] (frob_text.constprop.0) from [<c0084bb0>] (load_module+0x14b4/0x1d28)
> > [<c0084bb0>] (load_module) from [<c008562c>] (sys_finit_module+0xa0/0xc4)
> > [<c008562c>] (sys_finit_module) from [<c0009000>] (ret_fast_syscall+0x0/0x50)
> > Exception stack(0xce44ffa8 to 0xce44fff0)
> > ffa0: 0041c620 00000000 00000005 b6d17910 00000000 00000000
> > ffc0: 0041c620 00000000 00000000 0000017b 0041f078 00000000 004098b0 b6ebfe54
> > ffe0: bedb6bc8 bedb6bb8 b6d0f91c b6c945a0
> > Code: e7f001f2 e5931008 e1110002 0a000001 (e7f001f2)
> > ---[ end trace e904557128d9aed5 ]---
> >
> > Signed-off-by: He Zhe <zhe.he at windriver.com>
> > ---
> > This is for linux-yocto-dev all branches.
>
> The version information is important, and shouldnt be hidden down here.
> If you put it within the [PATCH ....] square bracket section, the
> maintainer/merger person will see it and the "git am" will throw it away
> once applied.
Fair points. Thanks, Paul.
Zhe
>
> Paul.
> --
>
> >
> > kernel/module.c | 7 +------
> > 1 file changed, 1 insertion(+), 6 deletions(-)
> >
> > diff --git a/kernel/module.c b/kernel/module.c
> > index 5933395..cd8df51 100644
> > --- a/kernel/module.c
> > +++ b/kernel/module.c
> > @@ -64,14 +64,9 @@
> >
> > /*
> > * Modules' sections will be aligned on page boundaries
> > - * to ensure complete separation of code and data, but
> > - * only when CONFIG_STRICT_MODULE_RWX=y
> > + * to ensure complete separation of code and data
> > */
> > -#ifdef CONFIG_STRICT_MODULE_RWX
> > # define debug_align(X) ALIGN(X, PAGE_SIZE)
> > -#else
> > -# define debug_align(X) (X)
> > -#endif
> >
> > /* If this is set, the section belongs in the init part of the module */
> > #define INIT_OFFSET_MASK (1UL << (BITS_PER_LONG-1))
> > --
> > 2.7.4
> >
> > --
> > _______________________________________________
> > linux-yocto mailing list
> > linux-yocto at yoctoproject.org
> > https://lists.yoctoproject.org/listinfo/linux-yocto
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