Messages in this thread | | | Date | Mon, 25 May 2015 10:56:31 -0000 | Subject | Re: [PATCH] ARM: module: Add ".ref.text" to arm unwind tables | From | vigneshr@codeauro ... |
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Forgot to add Maintainers. Adding them now.
> On 05/13/2015 08:20 AM, Vignesh Radhakrishnan wrote: >> Functions inside kernel modules that use __ref >> will end up being placed in .ARM.exidx.ref.text >> section by gcc. >> >> Currently we don't consider adding these functions >> to arm unwind tables. >> >> Hence, if we turn slub debug on by default we end up >> with the messages of this sort: >> >> unwind: Index not found bf0011e0 >> >> This is because slub debug saves stack trace of >> allocation's and free's. Therefore, we end up seeing >> a flood of these messages in dmesg since its not >> able to locate these functions. >> >> Fix this by adding .ref.text section to arm unwind tables. >> > > With this patch, I go from > > ------------[ cut here ]------------ > WARNING: CPU: 0 PID: 63 at drivers/misc/test.c:12 that_function+0x10/0x2c > [test]() > Modules linked in: test(P+) > CPU: 0 PID: 63 Comm: insmod Tainted: P 4.1.0-rc2+ #28 > Hardware name: ARM-Versatile PB > [<c001a590>] (unwind_backtrace) from [<c0017b84>] (show_stack+0x10/0x14) > [<c0017b84>] (show_stack) from [<c0022370>] > (warn_slowpath_common+0x78/0xb0) > [<c0022370>] (warn_slowpath_common) from [<c0022444>] > (warn_slowpath_null+0x1c/0x24) > [<c0022444>] (warn_slowpath_null) from [<bf000048>] > (that_function+0x10/0x2c [test]) > unwind: Index not found bf000048 > ---[ end trace 3e24f8edd90f3b27 ]--- > > to > > ------------[ cut here ]------------ > WARNING: CPU: 0 PID: 63 at drivers/misc/test.c:12 that_function+0x10/0x2c > [test]() > Modules linked in: test(P+) > CPU: 0 PID: 63 Comm: insmod Tainted: P 4.1.0-rc2+ #30 > Hardware name: ARM-Versatile PB > [<c001a5d0>] (unwind_backtrace) from [<c0017b84>] (show_stack+0x10/0x14) > [<c0017b84>] (show_stack) from [<c0022770>] > (warn_slowpath_common+0x78/0xb0) > [<c0022770>] (warn_slowpath_common) from [<c0022844>] > (warn_slowpath_null+0x1c/0x24) > [<c0022844>] (warn_slowpath_null) from [<bf000048>] > (that_function+0x10/0x2c [test]) > [<bf000048>] (that_function [test]) from [<bf002010>] > (awesome_module+0x10/0x1c [test]) > [<bf002010>] (awesome_module [test]) from [<c0009710>] > (do_one_initcall+0x80/0x1dc) > [<c0009710>] (do_one_initcall) from [<c02d14e0>] > (do_init_module+0x58/0x1a8) > [<c02d14e0>] (do_init_module) from [<c0063940>] > (load_module+0x170c/0x1c38) > [<c0063940>] (load_module) from [<c0063f38>] (SyS_init_module+0xcc/0x124) > [<c0063f38>] (SyS_init_module) from [<c0014900>] > (ret_fast_syscall+0x0/0x30) > ---[ end trace 554c9ff461eb2505 ]--- > > Tested-by: Laura Abbott <labbott@redhat.com> > >> Signed-off-by: Vignesh Radhakrishnan <vigneshr@codeaurora.org> >> --- >> arch/arm/include/asm/module.h | 1 + >> arch/arm/kernel/module.c | 4 ++++ >> 2 files changed, 5 insertions(+) >> >> diff --git a/arch/arm/include/asm/module.h >> b/arch/arm/include/asm/module.h >> index ed690c4..17640c9 100644 >> --- a/arch/arm/include/asm/module.h >> +++ b/arch/arm/include/asm/module.h >> @@ -14,6 +14,7 @@ enum { >> ARM_SEC_DEVEXIT, >> ARM_SEC_HOT, >> ARM_SEC_UNLIKELY, >> + ARM_SEC_REF, >> ARM_SEC_MAX, >> }; >> >> diff --git a/arch/arm/kernel/module.c b/arch/arm/kernel/module.c >> index 2e11961..846b888 100644 >> --- a/arch/arm/kernel/module.c >> +++ b/arch/arm/kernel/module.c >> @@ -308,6 +308,8 @@ int module_finalize(const Elf32_Ehdr *hdr, const >> Elf_Shdr *sechdrs, >> maps[ARM_SEC_UNLIKELY].unw_sec = s; >> else if (strcmp(".ARM.exidx.text.hot", secname) == 0) >> maps[ARM_SEC_HOT].unw_sec = s; >> + else if (strcmp(".ARM.exidx.ref.text", secname) == 0) >> + maps[ARM_SEC_REF].unw_sec = s; >> else if (strcmp(".init.text", secname) == 0) >> maps[ARM_SEC_INIT].txt_sec = s; >> else if (strcmp(".text", secname) == 0) >> @@ -318,6 +320,8 @@ int module_finalize(const Elf32_Ehdr *hdr, const >> Elf_Shdr *sechdrs, >> maps[ARM_SEC_UNLIKELY].txt_sec = s; >> else if (strcmp(".text.hot", secname) == 0) >> maps[ARM_SEC_HOT].txt_sec = s; >> + else if (strcmp(".ref.text", secname) == 0) >> + maps[ARM_SEC_REF].txt_sec = s; >> } >> >> for (i = 0; i < ARM_SEC_MAX; i++) >> > >
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