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From: Peter Zijlstra <peterz@infradead.org>
To: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>,
	linux-kernel@vger.kernel.org, x86@kernel.org,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Tim Chen <tim.c.chen@linux.intel.com>,
	Josh Poimboeuf <jpoimboe@kernel.org>,
	Andrew Cooper <Andrew.Cooper3@citrix.com>,
	Johannes Wikner <kwikner@ethz.ch>,
	Alyssa Milburn <alyssa.milburn@linux.intel.com>,
	Jann Horn <jannh@google.com>, "H.J. Lu" <hjl.tools@gmail.com>,
	Joao Moreira <joao.moreira@intel.com>,
	Joseph Nuzman <joseph.nuzman@intel.com>,
	Steven Rostedt <rostedt@goodmis.org>,
	Juergen Gross <jgross@suse.com>,
	Masami Hiramatsu <mhiramat@kernel.org>,
	Alexei Starovoitov <ast@kernel.org>,
	Daniel Borkmann <daniel@iogearbox.net>,
	K Prateek Nayak <kprateek.nayak@amd.com>,
	Eric Dumazet <edumazet@google.com>
Subject: Re: [PATCH v3 32/59] objtool: Allow STT_NOTYPE -> STT_FUNC+0 tail-calls
Date: Thu, 22 Sep 2022 12:47:26 +0200	[thread overview]
Message-ID: <Yyw9Pvo7/7YWoKds@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <Yyw5JqLtiXcqid3K@hirez.programming.kicks-ass.net>

On Thu, Sep 22, 2022 at 12:29:58PM +0200, Peter Zijlstra wrote:
> I managed to reproduce with 12.2.0 -- my 12.1.0 compiler didn't
> reproduce.
> 
> $ ./scripts/objdump-func vmlinux.o ftrace_replace_code

> 0000 0000000000012a83 <ftrace_replace_code.cold>:
> 0000    12a83:	48 89 de             	mov    %rbx,%rsi
> 0003    12a86:	89 c7                	mov    %eax,%edi
> 0005    12a88:	5b                   	pop    %rbx
> 0006    12a89:	5d                   	pop    %rbp
> 0007    12a8a:	41 5c                	pop    %r12
> 0009    12a8c:	41 5d                	pop    %r13
> 000b    12a8e:	41 5e                	pop    %r14
> 000d    12a90:	e9 62 fd ff ff       	jmp    127f7 <ftrace_bug>
> 
> 
> Seems to suggest objtool is actually right; I cannot find a reference to
> that cold symbol.

Ohhhh, ftrace_replace_cold is a weak function, so it could be the
original weak symbol had a reference to the cold thing.

We have some code to deal with crap like that, lemme try and figure out
what went wrong.

  reply	other threads:[~2022-09-22 10:47 UTC|newest]

Thread overview: 138+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-09-15 11:10 [PATCH v3 00/59] x86/retbleed: Call depth tracking mitigation Peter Zijlstra
2022-09-15 11:10 ` [PATCH v3 01/59] x86/paravirt: Ensure proper alignment Peter Zijlstra
2022-09-21 11:08   ` [tip: x86/paravirt] " tip-bot2 for Thomas Gleixner
2022-09-15 11:10 ` [PATCH v3 02/59] x86/cpu: Remove segment load from switch_to_new_gdt() Peter Zijlstra
2022-10-17 14:54   ` [tip: x86/core] " tip-bot2 for Thomas Gleixner
2022-09-15 11:10 ` [PATCH v3 03/59] x86/cpu: Get rid of redundant switch_to_new_gdt() invocations Peter Zijlstra
2022-10-17 14:54   ` [tip: x86/core] " tip-bot2 for Thomas Gleixner
2022-09-15 11:10 ` [PATCH v3 04/59] x86/cpu: Re-enable stackprotector Peter Zijlstra
2022-10-17 14:54   ` [tip: x86/core] " tip-bot2 for Thomas Gleixner
2022-09-15 11:10 ` [PATCH v3 05/59] x86/modules: Set VM_FLUSH_RESET_PERMS in module_alloc() Peter Zijlstra
2022-10-17 14:54   ` [tip: x86/core] " tip-bot2 for Thomas Gleixner
2022-09-15 11:10 ` [PATCH v3 06/59] x86/vdso: Ensure all kernel code is seen by objtool Peter Zijlstra
2022-10-17 14:54   ` [tip: x86/core] " tip-bot2 for Thomas Gleixner
2022-09-15 11:10 ` [PATCH v3 07/59] x86: Sanitize linker script Peter Zijlstra
2022-10-07 16:03   ` Borislav Petkov
2022-10-17 14:54   ` [tip: x86/core] " tip-bot2 for Thomas Gleixner
2022-09-15 11:10 ` [PATCH v3 08/59] arch: Introduce CONFIG_FUNCTION_ALIGNMENT Peter Zijlstra
2022-10-17 14:54   ` [tip: x86/core] " tip-bot2 for Peter Zijlstra
2022-09-15 11:10 ` [PATCH v3 09/59] x86/asm: Differentiate between code and function alignment Peter Zijlstra
2022-10-17 14:54   ` [tip: x86/core] " tip-bot2 for Thomas Gleixner
2022-09-15 11:10 ` [PATCH v3 10/59] x86/error_inject: Align function properly Peter Zijlstra
2022-10-17 14:54   ` [tip: x86/core] " tip-bot2 for Peter Zijlstra
2022-09-15 11:10 ` [PATCH v3 11/59] x86/paravirt: Properly align PV functions Peter Zijlstra
2022-09-15 14:34   ` Juergen Gross
2022-10-17 14:54   ` [tip: x86/core] " tip-bot2 for Thomas Gleixner
2022-09-15 11:10 ` [PATCH v3 12/59] x86/entry: Align SYM_CODE_START() variants Peter Zijlstra
2022-10-17 14:54   ` [tip: x86/core] " tip-bot2 for Thomas Gleixner
2022-09-15 11:10 ` [PATCH v3 13/59] crypto: x86/camellia: Remove redundant alignments Peter Zijlstra
2022-10-17 14:54   ` [tip: x86/core] " tip-bot2 for Thomas Gleixner
2022-09-15 11:10 ` [PATCH v3 14/59] crypto: x86/cast5: " Peter Zijlstra
2022-10-17 14:54   ` [tip: x86/core] " tip-bot2 for Thomas Gleixner
2022-09-15 11:10 ` [PATCH v3 15/59] crypto: x86/crct10dif-pcl: " Peter Zijlstra
2022-10-17 14:54   ` [tip: x86/core] " tip-bot2 for Thomas Gleixner
2022-09-15 11:10 ` [PATCH v3 16/59] crypto: x86/serpent: " Peter Zijlstra
2022-10-17 14:54   ` [tip: x86/core] " tip-bot2 for Thomas Gleixner
2022-09-15 11:10 ` [PATCH v3 17/59] crypto: x86/sha1: Remove custom alignments Peter Zijlstra
2022-10-17 14:54   ` [tip: x86/core] " tip-bot2 for Thomas Gleixner
2022-09-15 11:10 ` [PATCH v3 18/59] crypto: x86/sha256: " Peter Zijlstra
2022-10-17 14:54   ` [tip: x86/core] " tip-bot2 for Thomas Gleixner
2022-09-15 11:10 ` [PATCH v3 19/59] crypto: x86/sm[34]: Remove redundant alignments Peter Zijlstra
2022-10-17 14:54   ` [tip: x86/core] " tip-bot2 for Thomas Gleixner
2022-09-15 11:10 ` [PATCH v3 20/59] crypto: twofish: " Peter Zijlstra
2022-10-17 14:54   ` [tip: x86/core] " tip-bot2 for Thomas Gleixner
2022-09-15 11:11 ` [PATCH v3 21/59] crypto: x86/poly1305: Remove custom function alignment Peter Zijlstra
2022-10-17 14:54   ` [tip: x86/core] " tip-bot2 for Thomas Gleixner
2022-09-15 11:11 ` [PATCH v3 22/59] x86: Put hot per CPU variables into a struct Peter Zijlstra
2022-10-17 14:54   ` [tip: x86/core] " tip-bot2 for Thomas Gleixner
2022-09-15 11:11 ` [PATCH v3 23/59] x86/percpu: Move preempt_count next to current_task Peter Zijlstra
2022-10-17 14:54   ` [tip: x86/core] " tip-bot2 for Thomas Gleixner
2022-09-15 11:11 ` [PATCH v3 24/59] x86/percpu: Move cpu_number " Peter Zijlstra
2022-10-17 14:54   ` [tip: x86/core] " tip-bot2 for Thomas Gleixner
2022-09-15 11:11 ` [PATCH v3 25/59] x86/percpu: Move current_top_of_stack " Peter Zijlstra
2022-10-17 14:54   ` [tip: x86/core] " tip-bot2 for Thomas Gleixner
2022-09-15 11:11 ` [PATCH v3 26/59] x86/percpu: Move irq_stack variables " Peter Zijlstra
2022-10-17 14:54   ` [tip: x86/core] " tip-bot2 for Thomas Gleixner
2022-09-15 11:11 ` [PATCH v3 27/59] x86/softirq: Move softirq pending next to current task Peter Zijlstra
2022-10-17 14:54   ` [tip: x86/core] " tip-bot2 for Thomas Gleixner
2022-09-15 11:11 ` [PATCH v3 28/59] objtool: Allow !PC relative relocations Peter Zijlstra
2022-10-17 14:54   ` [tip: x86/core] " tip-bot2 for Peter Zijlstra
2022-09-15 11:11 ` [PATCH v3 29/59] objtool: Track init section Peter Zijlstra
2022-10-17 14:54   ` [tip: x86/core] " tip-bot2 for Peter Zijlstra
2022-09-15 11:11 ` [PATCH v3 30/59] objtool: Add .call_sites section Peter Zijlstra
2022-10-17 14:54   ` [tip: x86/core] " tip-bot2 for Peter Zijlstra
2022-09-15 11:11 ` [PATCH v3 31/59] objtool: Add --hacks=skylake Peter Zijlstra
2022-10-17 14:53   ` [tip: x86/core] " tip-bot2 for Peter Zijlstra
2022-09-15 11:11 ` [PATCH v3 32/59] objtool: Allow STT_NOTYPE -> STT_FUNC+0 tail-calls Peter Zijlstra
2022-09-22  5:27   ` Pawan Gupta
2022-09-22 10:29     ` Peter Zijlstra
2022-09-22 10:47       ` Peter Zijlstra [this message]
2022-09-22 13:15         ` Peter Zijlstra
2022-09-23 14:35           ` Peter Zijlstra
2022-09-23 17:36             ` Pawan Gupta
2022-09-15 11:11 ` [PATCH v3 33/59] objtool: Fix find_{symbol,func}_containing() Peter Zijlstra
2022-10-17 14:53   ` [tip: x86/core] " tip-bot2 for Peter Zijlstra
2022-09-15 11:11 ` [PATCH v3 34/59] objtool: Allow symbol range comparisons for IBT/ENDBR Peter Zijlstra
2022-10-17 14:53   ` [tip: x86/core] " tip-bot2 for Peter Zijlstra
2022-09-15 11:11 ` [PATCH v3 35/59] x86/entry: Make sync_regs() invocation a tail call Peter Zijlstra
2022-10-17 14:53   ` [tip: x86/core] " tip-bot2 for Peter Zijlstra
2022-09-15 11:11 ` [PATCH v3 36/59] ftrace: Add HAVE_DYNAMIC_FTRACE_NO_PATCHABLE Peter Zijlstra
2022-09-15 11:11 ` [PATCH v3 37/59] x86/putuser: Provide room for padding Peter Zijlstra
2022-10-17 14:53   ` [tip: x86/core] " tip-bot2 for Thomas Gleixner
2022-09-15 11:11 ` [PATCH v3 38/59] x86/Kconfig: Add CONFIG_CALL_THUNKS Peter Zijlstra
2022-10-17 14:53   ` [tip: x86/core] " tip-bot2 for Thomas Gleixner
2022-09-15 11:11 ` [PATCH v3 39/59] x86/Kconfig: Introduce function padding Peter Zijlstra
2022-10-17 14:53   ` [tip: x86/core] " tip-bot2 for Thomas Gleixner
2022-09-15 11:11 ` [PATCH v3 40/59] x86/retbleed: Add X86_FEATURE_CALL_DEPTH Peter Zijlstra
2022-10-17 14:53   ` [tip: x86/core] " tip-bot2 for Thomas Gleixner
2022-09-15 11:11 ` [PATCH v3 41/59] x86/alternatives: Provide text_poke_copy_locked() Peter Zijlstra
2022-10-17 14:53   ` [tip: x86/core] " tip-bot2 for Thomas Gleixner
2022-09-15 11:11 ` [PATCH v3 42/59] x86/entry: Make some entry symbols global Peter Zijlstra
2022-10-17 14:53   ` [tip: x86/core] " tip-bot2 for Thomas Gleixner
2022-09-15 11:11 ` [PATCH v3 43/59] x86/paravirt: Make struct paravirt_call_site unconditionally available Peter Zijlstra
2022-10-17 14:53   ` [tip: x86/core] " tip-bot2 for Thomas Gleixner
2022-09-15 11:11 ` [PATCH v3 44/59] x86/callthunks: Add call patching for call depth tracking Peter Zijlstra
2022-10-17 14:53   ` [tip: x86/core] " tip-bot2 for Thomas Gleixner
2022-09-15 11:11 ` [PATCH v3 45/59] x86/modules: Add call patching Peter Zijlstra
2022-10-17 14:53   ` [tip: x86/core] " tip-bot2 for Thomas Gleixner
2022-09-15 11:11 ` [PATCH v3 46/59] x86/returnthunk: Allow different return thunks Peter Zijlstra
2022-10-17 14:53   ` [tip: x86/core] " tip-bot2 for Peter Zijlstra
2022-09-15 11:11 ` [PATCH v3 47/59] x86/asm: Provide ALTERNATIVE_3 Peter Zijlstra
2022-10-17 14:53   ` [tip: x86/core] " tip-bot2 for Peter Zijlstra
2022-09-15 11:11 ` [PATCH v3 48/59] x86/retbleed: Add SKL return thunk Peter Zijlstra
2022-10-17 14:53   ` [tip: x86/core] " tip-bot2 for Thomas Gleixner
2022-10-20 23:10   ` [PATCH v3 48/59] " Nathan Chancellor
2022-10-21  9:53     ` Peter Zijlstra
2022-10-21 15:21       ` Nathan Chancellor
2022-11-03 22:53         ` KVM vs AMD: " Andrew Cooper
2022-11-04 12:44           ` Peter Zijlstra
2022-11-04 15:29             ` Andrew Cooper
2022-11-04 15:32             ` Nathan Chancellor
2022-11-07  9:37             ` Paolo Bonzini
2022-09-15 11:11 ` [PATCH v3 49/59] x86/retpoline: Add SKL retthunk retpolines Peter Zijlstra
2022-10-17 14:53   ` [tip: x86/core] " tip-bot2 for Peter Zijlstra
2022-09-15 11:11 ` [PATCH v3 50/59] x86/retbleed: Add SKL call thunk Peter Zijlstra
2022-10-17 14:53   ` [tip: x86/core] " tip-bot2 for Thomas Gleixner
2022-09-15 11:11 ` [PATCH v3 51/59] x86/calldepth: Add ret/call counting for debug Peter Zijlstra
2022-10-17 14:53   ` [tip: x86/core] " tip-bot2 for Thomas Gleixner
2022-09-15 11:11 ` [PATCH v3 52/59] static_call: Add call depth tracking support Peter Zijlstra
2022-10-17 14:53   ` [tip: x86/core] " tip-bot2 for Peter Zijlstra
2022-09-15 11:11 ` [PATCH v3 53/59] kallsyms: Take callthunks into account Peter Zijlstra
2022-10-17 14:53   ` [tip: x86/core] " tip-bot2 for Peter Zijlstra
2022-09-15 11:11 ` [PATCH v3 54/59] x86/orc: Make it callthunk aware Peter Zijlstra
2022-10-17 14:53   ` [tip: x86/core] " tip-bot2 for Peter Zijlstra
2022-09-15 11:11 ` [PATCH v3 55/59] x86/bpf: Emit call depth accounting if required Peter Zijlstra
2022-10-17 14:53   ` [tip: x86/core] " tip-bot2 for Thomas Gleixner
2023-01-05 21:49   ` [PATCH v3 55/59] " Joan Bruguera
2022-09-15 11:11 ` [PATCH v3 56/59] x86/ftrace: Remove ftrace_epilogue() Peter Zijlstra
2022-10-17 14:53   ` [tip: x86/core] " tip-bot2 for Peter Zijlstra
2022-10-20 15:17   ` [tip: x86/urgent] " tip-bot2 for Peter Zijlstra
2022-12-09 15:41   ` [PATCH v3 56/59] " Steven Rostedt
2022-09-15 11:11 ` [PATCH v3 57/59] x86/ftrace: Rebalance RSB Peter Zijlstra
2022-10-17 14:53   ` [tip: x86/core] " tip-bot2 for Peter Zijlstra
2022-09-15 11:11 ` [PATCH v3 58/59] x86/ftrace: Make it call depth tracking aware Peter Zijlstra
2022-09-21 10:19   ` [PATCH v3.1 " Peter Zijlstra
2022-09-21 18:45     ` Pawan Gupta
2022-10-17 14:53   ` [tip: x86/core] " tip-bot2 for Peter Zijlstra
2022-09-15 11:11 ` [PATCH v3 59/59] x86/retbleed: Add call depth tracking mitigation Peter Zijlstra
2022-10-17 14:53   ` [tip: x86/core] " tip-bot2 for Thomas Gleixner

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