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 2247543AB0 for ; Tue, 13 Aug 2024 06:28:21 +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=1723530502; cv=none; b=UOEl05i0IHwiAayfkx9FnS1FJ71G0eFkVr+I7u4b87OZW1+0tkyAGAdieVMUCp5+i9mR15TC0AITh4Vp8QnPFd6yCizyc0Eu/dKUWu39iXsptozdPCFO+RdkUTSsAd+8GWPbfYR/8BRbapNLhmq/f25U2hDeGmhzS504OO0XUMQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1723530502; c=relaxed/simple; bh=ka60lIgJqx8poGwiVEs4DWeOUKVUdSaQavPUrnZRmkk=; h=Date:To:From:Subject:Message-Id; b=jbaRPh9igF9Q1v4HBCvCdLknPn5Wh+1oabojJcNGiVpZkmkeBsRPqxKIVrNGrNV+uwCoNmQuvRji3AFtPJ62byh2/wkW6RXQ3hJUHoWndKEjnVfn/7lNmnk7Lb3wAtq6vud2tHt2+apxvuWhUWUE0V1KiU3M8xAeD2yQqudbFy8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b=wRlX758+; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b="wRlX758+" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 92DCBC4AF0B; Tue, 13 Aug 2024 06:28:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1723530501; bh=ka60lIgJqx8poGwiVEs4DWeOUKVUdSaQavPUrnZRmkk=; h=Date:To:From:Subject:From; b=wRlX758+wpfgJbZJOz2nhn6OrVh9HjD3fi+2Xatjzw8Ms3CaqrA/fG/+P7jWNuitE +l6b9k4QmDCrBa3dZaDZ1X56QGPxTTOaplW11bUOg93CdWjhXFJ5vTkwuCR9ORCEd5 t/iUxpTo3mut3RMTWehXBT2CSq/zLFgSxbAT7ysw= Date: Mon, 12 Aug 2024 23:28:20 -0700 To: mm-commits@vger.kernel.org,vgoyal@redhat.com,paul.walmsley@sifive.com,palmer@dabbelt.com,dyoung@redhat.com,catalin.marinas@arm.com,bhe@redhat.com,aou@eecs.berkeley.edu,ruanjinjie@huawei.com,akpm@linux-foundation.org From: Andrew Morton Subject: + crash-fix-riscv64-crash-memory-reserve-dead-loop.patch added to mm-hotfixes-unstable branch Message-Id: <20240813062821.92DCBC4AF0B@smtp.kernel.org> Precedence: bulk X-Mailing-List: mm-commits@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: The patch titled Subject: crash: fix riscv64 crash memory reserve dead loop has been added to the -mm mm-hotfixes-unstable branch. Its filename is crash-fix-riscv64-crash-memory-reserve-dead-loop.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/crash-fix-riscv64-crash-memory-reserve-dead-loop.patch This patch will later appear in the mm-hotfixes-unstable branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next via the mm-everything branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm and is updated there every 2-3 working days ------------------------------------------------------ From: Jinjie Ruan Subject: crash: fix riscv64 crash memory reserve dead loop Date: Mon, 12 Aug 2024 14:20:17 +0800 On RISCV64 Qemu machine with 512MB memory, cmdline "crashkernel=500M,high" will cause system stall as below: Zone ranges: DMA32 [mem 0x0000000080000000-0x000000009fffffff] Normal empty Movable zone start for each node Early memory node ranges node 0: [mem 0x0000000080000000-0x000000008005ffff] node 0: [mem 0x0000000080060000-0x000000009fffffff] Initmem setup node 0 [mem 0x0000000080000000-0x000000009fffffff] (stall here) commit 5d99cadf1568 ("crash: fix x86_32 crash memory reserve dead loop bug") fix this on 32-bit architecture. However, the problem is not completely solved. If `CRASH_ADDR_LOW_MAX = CRASH_ADDR_HIGH_MAX` on 64-bit architecture, for example, when system memory is equal to CRASH_ADDR_LOW_MAX on RISCV64, the following infinite loop will also occur: -> reserve_crashkernel_generic() and high is true -> alloc at [CRASH_ADDR_LOW_MAX, CRASH_ADDR_HIGH_MAX] fail -> alloc at [0, CRASH_ADDR_LOW_MAX] fail and repeatedly (because CRASH_ADDR_LOW_MAX = CRASH_ADDR_HIGH_MAX). As Catalin suggested, do not remove the ",high" reservation fallback to ",low" logic which will change arm64's kdump behavior, but fix it by skipping the above situation similar to commit d2f32f23190b ("crash: fix x86_32 crash memory reserve dead loop"). After this patch, it print: cannot allocate crashkernel (size:0x1f400000) Link: https://lkml.kernel.org/r/20240812062017.2674441-1-ruanjinjie@huawei.com Signed-off-by: Jinjie Ruan Suggested-by: Catalin Marinas Reviewed-by: Catalin Marinas Acked-by: Baoquan He Cc: Albert Ou Cc: Dave Young Cc: Palmer Dabbelt Cc: Paul Walmsley Cc: Vivek Goyal Signed-off-by: Andrew Morton --- kernel/crash_reserve.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) --- a/kernel/crash_reserve.c~crash-fix-riscv64-crash-memory-reserve-dead-loop +++ a/kernel/crash_reserve.c @@ -423,7 +423,8 @@ retry: if (high && search_end == CRASH_ADDR_HIGH_MAX) { search_end = CRASH_ADDR_LOW_MAX; search_base = 0; - goto retry; + if (search_end != CRASH_ADDR_HIGH_MAX) + goto retry; } pr_warn("cannot allocate crashkernel (size:0x%llx)\n", crash_size); _ Patches currently in -mm which might be from ruanjinjie@huawei.com are crash-fix-riscv64-crash-memory-reserve-dead-loop.patch crash-fix-crash-memory-reserve-exceed-system-memory-bug.patch