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a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1688378312; h=from:from:sender:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=ucJo8aXSMxIWjvyiuQL+IC2PERCi+4TDpcBkPo0c10U=; b=USq9QKtUXUFAtTXjQ28yrB8mdvtSjqCRkwTbLdobtTtaVwmMaBmunwPxVC0ZfAwFsSegc4 C2eUWgMqhZa/unl61izLzi9i8khSYt83ShaN1o664mGQTTHBxDztztwrXcXnmHI+QN6dJG omRKE3j4HQEoiAMFnxgk21AcmUFfSuA= Received: from [2a02:8108:8980:2478:8cde:aa2c:f324:937e]; authenticated by wp530.webpack.hosteurope.de running ExIM with esmtpsa (TLS1.3:ECDHE_RSA_AES_128_GCM_SHA256:128) id 1qGGJz-0002ai-71; Mon, 03 Jul 2023 11:58:15 +0200 Message-ID: Date: Mon, 3 Jul 2023 11:58:13 +0200 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.12.0 Reply-To: Linux regressions mailing list Subject: Re: [PATCH v4 29/33] x86/mm: try VMA lock-based page fault handling first Content-Language: en-US, de-DE To: Jiri Slaby , Suren Baghdasaryan , akpm@linux-foundation.org Cc: michel@lespinasse.org, jglisse@google.com, mhocko@suse.com, vbabka@suse.cz, hannes@cmpxchg.org, mgorman@techsingularity.net, dave@stgolabs.net, willy@infradead.org, liam.howlett@oracle.com, peterz@infradead.org, ldufour@linux.ibm.com, paulmck@kernel.org, mingo@redhat.com, will@kernel.org, luto@kernel.org, songliubraving@fb.com, peterx@redhat.com, david@redhat.com, dhowells@redhat.com, hughd@google.com, bigeasy@linutronix.de, kent.overstreet@linux.dev, punit.agrawal@bytedance.com, lstoakes@gmail.com, peterjung1337@gmail.com, rientjes@google.com, chriscli@google.com, axelrasmussen@google.com, joelaf@google.com, minchan@google.com, rppt@kernel.org, jannh@google.com, shakeelb@google.com, tatashin@google.com, edumazet@google.com, gthelen@google.com, gurua@google.com, arjunroy@google.com, soheil@google.com, leewalsh@google.com, posk@google.com, michalechner92@googlemail.com, linux-mm@kvack.org, linux-arm-kernel@lists.infradead.org, linuxppc-dev@lists.ozlabs.org, x86@kernel.org, linux-kernel@vger.kernel.org, kernel-team@android.com References: <20230227173632.3292573-1-surenb@google.com> <20230227173632.3292573-30-surenb@google.com> From: "Linux regression tracking (Thorsten Leemhuis)" In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-bounce-key: webpack.hosteurope.de;regressions@leemhuis.info;1688378311;9fdbedf2; X-HE-SMSGID: 1qGGJz-0002ai-71 X-Rspamd-Server: rspam08 X-Rspamd-Queue-Id: CCF4840018 X-Stat-Signature: 5g4b3tg6x4k5rs4zuyih6ra6p6gx95nf X-Rspam-User: X-HE-Tag: 1688378311-954359 X-HE-Meta: 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 jtsPwNQ1 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 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On 29.06.23 16:40, Jiri Slaby wrote: > On 27. 02. 23, 18:36, Suren Baghdasaryan wrote: >> Attempt VMA lock-based page fault handling first, and fall back to the >> existing mmap_lock-based handling if that fails. >> >> Signed-off-by: Suren Baghdasaryan >> --- >>   arch/x86/Kconfig    |  1 + >>   arch/x86/mm/fault.c | 36 ++++++++++++++++++++++++++++++++++++ >>   2 files changed, 37 insertions(+) >> >> diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig >> index a825bf031f49..df21fba77db1 100644 >> --- a/arch/x86/Kconfig >> +++ b/arch/x86/Kconfig >> @@ -27,6 +27,7 @@ config X86_64 >>       # Options that are inherently 64-bit kernel only: >>       select ARCH_HAS_GIGANTIC_PAGE >>       select ARCH_SUPPORTS_INT128 if CC_HAS_INT128 >> +    select ARCH_SUPPORTS_PER_VMA_LOCK >>       select ARCH_USE_CMPXCHG_LOCKREF >>       select HAVE_ARCH_SOFT_DIRTY >>       select MODULES_USE_ELF_RELA >> diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c >> index a498ae1fbe66..e4399983c50c 100644 >> --- a/arch/x86/mm/fault.c >> +++ b/arch/x86/mm/fault.c >> @@ -19,6 +19,7 @@ >>   #include         /* faulthandler_disabled()    */ >>   #include             /* >> efi_crash_gracefully_on_page_fault()*/ >>   #include >> +#include             /* find_and_lock_vma() */ >>     #include         /* boot_cpu_has, ...        */ >>   #include             /* dotraplinkage, ...        */ >> @@ -1333,6 +1334,38 @@ void do_user_addr_fault(struct pt_regs *regs, >>       } >>   #endif >>   +#ifdef CONFIG_PER_VMA_LOCK >> +    if (!(flags & FAULT_FLAG_USER)) >> +        goto lock_mmap; >> + >> +    vma = lock_vma_under_rcu(mm, address); >> +    if (!vma) >> +        goto lock_mmap; >> + >> +    if (unlikely(access_error(error_code, vma))) { >> +        vma_end_read(vma); >> +        goto lock_mmap; >> +    } >> +    fault = handle_mm_fault(vma, address, flags | >> FAULT_FLAG_VMA_LOCK, regs); >> +    vma_end_read(vma); >> + >> +    if (!(fault & VM_FAULT_RETRY)) { >> +        count_vm_vma_lock_event(VMA_LOCK_SUCCESS); >> +        goto done; >> +    } >> +    count_vm_vma_lock_event(VMA_LOCK_RETRY); > > This is apparently not strong enough as it causes go build failures like: TWIMC & for the record: there is another report about trouble caused by this change; for details see https://bugzilla.kernel.org/show_bug.cgi?id=217624 And a "forward to devs and lists" thread about that report: https://lore.kernel.org/all/facbfec3-837a-51ed-85fa-31021c17d6ef@gmail.com/ Ciao, Thorsten (wearing his 'the Linux kernel's regression tracker' hat) -- Everything you wanna know about Linux kernel regression tracking: https://linux-regtracking.leemhuis.info/about/#tldr If I did something stupid, please tell me, as explained on that page. > [  409s] strconv > [  409s] releasep: m=0x579e2000 m->p=0x5781c600 p->m=0x0 p->status=2 > [  409s] fatal error: releasep: invalid p state > [  409s] > > [  325s] hash/adler32 > [  325s] hash/crc32 > [  325s] cmd/internal/codesign > [  336s] fatal error: runtime: out of memory > > There are many kinds of similar errors. It happens in 1-3 out of 20 > builds only. > > If I revert the commit on top of 6.4, they all dismiss. Any idea? > > The downstream report: > https://bugzilla.suse.com/show_bug.cgi?id=1212775 > >> + >> +    /* Quick path to respond to signals */ >> +    if (fault_signal_pending(fault, regs)) { >> +        if (!user_mode(regs)) >> +            kernelmode_fixup_or_oops(regs, error_code, address, >> +                         SIGBUS, BUS_ADRERR, >> +                         ARCH_DEFAULT_PKEY); >> +        return; >> +    } >> +lock_mmap: >> +#endif /* CONFIG_PER_VMA_LOCK */ >> + >>       /* >>        * Kernel-mode access to the user address space should only occur >>        * on well-defined single instructions listed in the exception >> @@ -1433,6 +1466,9 @@ void do_user_addr_fault(struct pt_regs *regs, >>       } >>         mmap_read_unlock(mm); >> +#ifdef CONFIG_PER_VMA_LOCK >> +done: >> +#endif >>       if (likely(!(fault & VM_FAULT_ERROR))) >>           return; >>   > > thanks,