From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 14B5847F51 for ; Tue, 23 Apr 2024 08:53:02 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1713862383; cv=none; b=OyPol5RxQa/kusWg+Bn8u5TsDBAVmMgswvN5epS6QCuqw+YVlLNVEHouujLUNgFUyZs+80OukTxzF3UUfEaFIZwfJnuLelmvoUD6RwwzoH6OJBZfiwyjNodkvSEJXb4pQFeIPv5V7k5rLjXjeJPy1xrH83pzwz9KatxVicx4j5k= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1713862383; c=relaxed/simple; bh=vmGKk8QfbCJLHyA/vTdFNvla0GjMsTsITrM85VN3KT8=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=bCvZ32nGPIyzxt0yTMQwgAAe/ZOJPuMGpGsUqdfOW6qvBcNZbnKB2fGiOfIzs1MbliiP7ffCh3Uxk20dbV5FlHWwZFF4UeWiFp4mw6CrQgZ0vmVV4SYST6udvAQq8DSUNtcWe4kU/w0VmjOcGq3WKMLNov8yhJ9BZzD6BHv4BWA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=ACqwC38t; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="ACqwC38t" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 25CB3C2BD11; Tue, 23 Apr 2024 08:53:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1713862382; bh=vmGKk8QfbCJLHyA/vTdFNvla0GjMsTsITrM85VN3KT8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ACqwC38tXGqS5kIY2MboEdPG4aGyGluSghRk3iXYJyCSn7qzw7gj84BhpFVa3mSqJ XZ1w0cZoyYB98zUGISEoU2Mk/Mny1pRdxpkELLFNRqk83o5rU3HuqEshoimF5bL6NF b557ZJRguxc4UzQK0AC5+ma0eXUviw6gpAmlGgSbfYkMCpotSlFQ1j9o4hvHc4zRmb 0OYVyxVMKZ0j46dPagtyxKMe1CXt67IVHTLEOUpHcL9ZH4V7MsV7aipct5qXQtii59 Yyizg+1VcEkfAFDMcMHFvpNkZOHVj9U9iek7QbBpn994Hf6uRQ3Rkme46CmEzk2o9k iKCMnOCoMK73A== From: Naveen N Rao To: stable@vger.kernel.org Cc: Greg KH Subject: [PATCH 6.6.y] powerpc/ftrace: Ignore ftrace locations in exit text sections Date: Tue, 23 Apr 2024 14:17:17 +0530 Message-ID: <20240423084717.286596-1-naveen@kernel.org> X-Mailer: git-send-email 2.44.0 In-Reply-To: <2024021902-authentic-handpick-da09@gregkh> References: <2024021902-authentic-handpick-da09@gregkh> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit commit ea73179e64131bcd29ba6defd33732abdf8ca14b upstream. Michael reported that we are seeing an ftrace bug on bootup when KASAN is enabled and we are using -fpatchable-function-entry: ftrace: allocating 47780 entries in 18 pages ftrace-powerpc: 0xc0000000020b3d5c: No module provided for non-kernel address ------------[ ftrace bug ]------------ ftrace faulted on modifying [] 0xc0000000020b3d5c Initializing ftrace call sites ftrace record flags: 0 (0) expected tramp: c00000000008cef4 ------------[ cut here ]------------ WARNING: CPU: 0 PID: 0 at kernel/trace/ftrace.c:2180 ftrace_bug+0x3c0/0x424 Modules linked in: CPU: 0 PID: 0 Comm: swapper Not tainted 6.5.0-rc3-00120-g0f71dcfb4aef #860 Hardware name: IBM pSeries (emulated by qemu) POWER9 (raw) 0x4e1202 0xf000005 of:SLOF,HEAD hv:linux,kvm pSeries NIP: c0000000003aa81c LR: c0000000003aa818 CTR: 0000000000000000 REGS: c0000000033cfab0 TRAP: 0700 Not tainted (6.5.0-rc3-00120-g0f71dcfb4aef) MSR: 8000000002021033 CR: 28028240 XER: 00000000 CFAR: c0000000002781a8 IRQMASK: 3 ... NIP [c0000000003aa81c] ftrace_bug+0x3c0/0x424 LR [c0000000003aa818] ftrace_bug+0x3bc/0x424 Call Trace: ftrace_bug+0x3bc/0x424 (unreliable) ftrace_process_locs+0x5f4/0x8a0 ftrace_init+0xc0/0x1d0 start_kernel+0x1d8/0x484 With CONFIG_FTRACE_MCOUNT_USE_PATCHABLE_FUNCTION_ENTRY=y and CONFIG_KASAN=y, compiler emits nops in functions that it generates for registering and unregistering global variables (unlike with -pg and -mprofile-kernel where calls to _mcount() are not generated in those functions). Those functions then end up in INIT_TEXT and EXIT_TEXT respectively. We don't expect to see any profiled functions in EXIT_TEXT, so ftrace_init_nop() assumes that all addresses that aren't in the core kernel text belongs to a module. Since these functions do not match that criteria, we see the above bug. Address this by having ftrace ignore all locations in the text exit sections of vmlinux. Fixes: 0f71dcfb4aef ("powerpc/ftrace: Add support for -fpatchable-function-entry") Cc: stable@vger.kernel.org # v6.6+ Reported-by: Michael Ellerman Signed-off-by: Naveen N Rao Reviewed-by: Benjamin Gray Signed-off-by: Michael Ellerman Link: https://msgid.link/20240213175410.1091313-1-naveen@kernel.org --- arch/powerpc/include/asm/ftrace.h | 10 ++-------- arch/powerpc/include/asm/sections.h | 1 + arch/powerpc/kernel/trace/ftrace.c | 12 ++++++++++++ arch/powerpc/kernel/trace/ftrace_64_pg.c | 5 +++++ arch/powerpc/kernel/vmlinux.lds.S | 2 ++ 5 files changed, 22 insertions(+), 8 deletions(-) diff --git a/arch/powerpc/include/asm/ftrace.h b/arch/powerpc/include/asm/ftrace.h index 9e5a39b6a311..107fc5a48456 100644 --- a/arch/powerpc/include/asm/ftrace.h +++ b/arch/powerpc/include/asm/ftrace.h @@ -20,14 +20,6 @@ #ifndef __ASSEMBLY__ extern void _mcount(void); -static inline unsigned long ftrace_call_adjust(unsigned long addr) -{ - if (IS_ENABLED(CONFIG_ARCH_USING_PATCHABLE_FUNCTION_ENTRY)) - addr += MCOUNT_INSN_SIZE; - - return addr; -} - unsigned long prepare_ftrace_return(unsigned long parent, unsigned long ip, unsigned long sp); @@ -142,8 +134,10 @@ static inline u8 this_cpu_get_ftrace_enabled(void) { return 1; } #ifdef CONFIG_FUNCTION_TRACER extern unsigned int ftrace_tramp_text[], ftrace_tramp_init[]; void ftrace_free_init_tramp(void); +unsigned long ftrace_call_adjust(unsigned long addr); #else static inline void ftrace_free_init_tramp(void) { } +static inline unsigned long ftrace_call_adjust(unsigned long addr) { return addr; } #endif #endif /* !__ASSEMBLY__ */ diff --git a/arch/powerpc/include/asm/sections.h b/arch/powerpc/include/asm/sections.h index ea26665f82cf..f43f3a6b0051 100644 --- a/arch/powerpc/include/asm/sections.h +++ b/arch/powerpc/include/asm/sections.h @@ -14,6 +14,7 @@ typedef struct func_desc func_desc_t; extern char __head_end[]; extern char __srwx_boundary[]; +extern char __exittext_begin[], __exittext_end[]; /* Patch sites */ extern s32 patch__call_flush_branch_caches1; diff --git a/arch/powerpc/kernel/trace/ftrace.c b/arch/powerpc/kernel/trace/ftrace.c index 82010629cf88..d8d6b4fd9a14 100644 --- a/arch/powerpc/kernel/trace/ftrace.c +++ b/arch/powerpc/kernel/trace/ftrace.c @@ -27,10 +27,22 @@ #include #include #include +#include #define NUM_FTRACE_TRAMPS 2 static unsigned long ftrace_tramps[NUM_FTRACE_TRAMPS]; +unsigned long ftrace_call_adjust(unsigned long addr) +{ + if (addr >= (unsigned long)__exittext_begin && addr < (unsigned long)__exittext_end) + return 0; + + if (IS_ENABLED(CONFIG_ARCH_USING_PATCHABLE_FUNCTION_ENTRY)) + addr += MCOUNT_INSN_SIZE; + + return addr; +} + static ppc_inst_t ftrace_create_branch_inst(unsigned long ip, unsigned long addr, int link) { ppc_inst_t op; diff --git a/arch/powerpc/kernel/trace/ftrace_64_pg.c b/arch/powerpc/kernel/trace/ftrace_64_pg.c index 7b85c3b460a3..12fab1803bcf 100644 --- a/arch/powerpc/kernel/trace/ftrace_64_pg.c +++ b/arch/powerpc/kernel/trace/ftrace_64_pg.c @@ -37,6 +37,11 @@ #define NUM_FTRACE_TRAMPS 8 static unsigned long ftrace_tramps[NUM_FTRACE_TRAMPS]; +unsigned long ftrace_call_adjust(unsigned long addr) +{ + return addr; +} + static ppc_inst_t ftrace_call_replace(unsigned long ip, unsigned long addr, int link) { diff --git a/arch/powerpc/kernel/vmlinux.lds.S b/arch/powerpc/kernel/vmlinux.lds.S index 1c5970df3233..f420df7888a7 100644 --- a/arch/powerpc/kernel/vmlinux.lds.S +++ b/arch/powerpc/kernel/vmlinux.lds.S @@ -281,7 +281,9 @@ SECTIONS * to deal with references from __bug_table */ .exit.text : AT(ADDR(.exit.text) - LOAD_OFFSET) { + __exittext_begin = .; EXIT_TEXT + __exittext_end = .; } . = ALIGN(PAGE_SIZE); base-commit: ba151416051a45ffca565f708584b9cd5c971481 -- 2.44.0