Messages in this thread | | | Subject | Re: Problems with commit 'kallsyms: add support for relative offsets in kallsyms address table' (in mmotm) | From | Guenter Roeck <> | Date | Sat, 23 Jan 2016 18:35:46 -0800 |
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On 01/23/2016 06:06 PM, Guenter Roeck wrote: > Hi, > > I see runtime problems with the current mmotm branch. All qemu mips targets > (32 and 64 bit, big and little endian) are stuck in boot after this commit. > > Bisect points to commit d13682e4d9d2 ("kallsyms: add support for relative offsets > in kallsyms address table". Disabling CONFIG_KALLSYMS_BASE_RELATIVE fixes the problem, > ie I can boot the image with qemu. > > Bisect log is attached. > > Playing with the problem, I found the following: > > 1) The problem is only seen with a toolchain using binutils 2.22, but not > with a toolchain using binutils 2.25. The compiler configuration may be > different for both toolchains. > 2) Message "kallsyms failure: absolute symbol value 0xffffffff807afd14 out of range > in relative mode" (twice) when using the toolchain with binutils 2.22. > This does not cause the build to fail, though. > 3) kallsyms_sym_address() parameter variable type is "int". In the calling code, > the variable type used is "unsigned long". That has no impact on the problem, > though. >
An additional data point: When using the older toolchain, many symbols in System.map are marked "A". ffffffff80100000 A _text With the more recent toolchain, the same symbols are marked "T". ffffffff80100000 T _text
Guenter
> Please let me know if there is anything I can do to help tracking down the problem. > > Thanks, > Guenter > > --- > # bad: [437b7ef6d6484bb36afb2c75897e14bf03113dbd] pci: test for unexpectedly disabled bridges > # good: [afd2ff9b7e1b367172f18ba7f693dfb62bdcb2dc] Linux 4.4 > git bisect start 'HEAD' 'v4.4' > # bad: [10078c1820d81131bc338c7c919feb2638a912ad] ocfs2: o2hb: add NEGOTIATE_APPROVE message > git bisect bad 10078c1820d81131bc338c7c919feb2638a912ad > # bad: [1b06048b37e888edb609e1509070ec0c6580eedd] kallsyms-add-support-for-relative-offsets-in-kallsyms-address-table-fix > git bisect bad 1b06048b37e888edb609e1509070ec0c6580eedd > # good: [ed312d94332968c86f53295795a3d122fd32cea2] arch/alpha/kernel/systbls.S: remove debug check > git bisect good ed312d94332968c86f53295795a3d122fd32cea2 > # good: [1cbe7000217b0126821ecd8fba0ba5f9315a0560] thp: limit number of object to scan on deferred_split_scan() > git bisect good 1cbe7000217b0126821ecd8fba0ba5f9315a0560 > # good: [474324b13e8184aa088c722b771f0f31ab773476] vmstat: remove BUG_ON from vmstat_update > git bisect good 474324b13e8184aa088c722b771f0f31ab773476 > # good: [d94a9840c248207040d62ca0f380943db9423418] proc: fix missing reference of mm > git bisect good d94a9840c248207040d62ca0f380943db9423418 > # bad: [d13682e4d9d2ad8220354b5e1a2bd6623e1f2e38] kallsyms: add support for relative offsets in kallsyms address table > git bisect bad d13682e4d9d2ad8220354b5e1a2bd6623e1f2e38 > # first bad commit: [d13682e4d9d2ad8220354b5e1a2bd6623e1f2e38] kallsyms: add support for relative offsets in kallsyms address table
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