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([95.67.15.120]) by smtp.gmail.com with ESMTPSA id a640c23a62f3a-ac7192e7d36sm113585466b.77.2025.03.28.00.09.51 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 28 Mar 2025 00:09:52 -0700 (PDT) X-BeenThere: xen-devel@lists.xenproject.org List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Errors-To: xen-devel-bounces@lists.xenproject.org Precedence: list Sender: "Xen-devel" X-Inumbo-ID: a61b3b33-0ba3-11f0-9ea3-5ba50f476ded DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1743145793; x=1743750593; darn=lists.xenproject.org; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:from:to:cc:subject:date:message-id:reply-to; bh=pgnirDI5Z6jVdU8BzlRjfzaNqqaKOUcJC3vL34SH97E=; b=JPyfQby3N2J1B8PtnvJq5DjTsW5JeJqdYIATEvx+LKhdmwq8LQ7IQzOCKqIPxLHUfD 2i+dWwZlJIdFkpK1hXkvPQYMmiGddM3d3rz2w0CgbIHmfbopmaHelXuO1X/hmU1i1P2n ywBFtlT+dhIaIrbOxwfzFQACtlJ6Y8ECvkIWKMan7RXUGLl4U0q5OEMcR99PqXuiT/XT 280pVrXxBLN4c0eHGXZ+SDtogJHwla2gmcQecI4JlAqMB3YaaQ8f+2vX9J7eFQq1wWyV itzumEo2oTNdqL8Ey+gDUD0raonwP5i/aGyK3jw8EXFkC59Uw6zuhbeFGFsua5cAgNrq 1uhA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1743145793; x=1743750593; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=pgnirDI5Z6jVdU8BzlRjfzaNqqaKOUcJC3vL34SH97E=; b=atbXPdF239XufpWJtZPFnF1vYvdRHnFyuOeQAw/IPoXq3e2oOWGCEWGLQPoQbklPVw dR6cbg3DuM9U4/iBSCxuAwZa6unmoJM6+YvUxdDjjJgs5+JoD1dX4Jyws8QhYyWc+707 tViO2flKpAbc87EByFHMZAH4UFWpk3b2r/vpAXh+BM4v9pXDIT1aNL+f4BLF6U6PIqDy w8SQrLpRLwprghzU36A3AihsUmXoVmeFR8UcfscivmZpMq0f4uRKcoaEtLJKKd6NKwCR gdTo3RTjolwHbogOv6xpUIdETqQT3Vg3elKSTU0jl0OZIg+r1ZDIB8AodAIvZC3P9Vnw xeJQ== X-Gm-Message-State: AOJu0YyTvnaJw5EOmMt/gqLx94eZS+H9vqdd013U3env+4v9qppda+a2 5oGI0zIojrKLG4otSStj9urAXXGESVu04xhxatlHUX3HTCv7wDk8IQxJqg== X-Gm-Gg: ASbGncvDdbnJv3zpKlvkBRUP1hAc/sS2WwTeTG2EZggjMPfrqBII16BoYc+WQXf9CAx XLANiFdsM7n9E++fphSfJknEuZ03YWccoCxeDUGwJl+Q/SLyEnNPI4+pO20tZT9H6mptMMrpd+O DTISYVdNdL9OxBdViFV7M2DDTdPPxTbe1tAGT1Ae3WudrTO3AuB9S9V6Ua35+qSBwsf9+S7u1wB huCgqkcy4sskIkKQpmVQ36mvwOQ/JQDRUwEXjJ+6F/NuGhtOwS0kKiRWUyjKnoi9V7K6PJy7y6r MDyCvMajnbvfFlonmMqjrcpskfuXLmdbW9PFY3CPMRfvWtTut4GtOe+J6kUasZ54ZISYCBfk20D j4n87vheY2FlyoUnixo4= X-Google-Smtp-Source: AGHT+IH8yNxZW7Q/KzLPPZ87s2aTgfSNmKKJ2ScX6hHjamY672pz8vID3rMVyz2XoCz1T7Is3PjRtw== X-Received: by 2002:a17:907:6d05:b0:ac4:4c5:9f26 with SMTP id a640c23a62f3a-ac6fb0fcadamr624132166b.38.1743145792773; Fri, 28 Mar 2025 00:09:52 -0700 (PDT) From: Mykola Kvach To: xen-devel@lists.xenproject.org Cc: Mykyta Poturai , Andrew Cooper , Anthony PERARD , Michal Orzel , Jan Beulich , Julien Grall , =?utf-8?q?Roger_Pau_Monn=C3=A9?= , Stefano Stabellini , Mykola Kvach Subject: [PATCH v3] xen/percpu: don't initialize percpu on resume Date: Fri, 28 Mar 2025 09:09:48 +0200 Message-ID: X-Mailer: git-send-email 2.43.0 MIME-Version: 1.0 From: Mykyta Poturai Invocation of the CPU_UP_PREPARE notification on ARM64 during resume causes a crash: (XEN) [ 315.807606] Error bringing CPU1 up: -16 (XEN) [ 315.811926] Xen BUG at common/cpu.c:258 [...] (XEN) [ 316.142765] Xen call trace: (XEN) [ 316.146048] [<00000a0000202264>] enable_nonboot_cpus+0x128/0x1ac (PC) (XEN) [ 316.153219] [<00000a000020225c>] enable_nonboot_cpus+0x120/0x1ac (LR) (XEN) [ 316.160391] [<00000a0000278180>] suspend.c#system_suspend+0x4c/0x1a0 (XEN) [ 316.167476] [<00000a0000206b70>] domain.c#continue_hypercall_tasklet_handler+0x54/0xd0 (XEN) [ 316.176117] [<00000a0000226538>] tasklet.c#do_tasklet_work+0xb8/0x100 (XEN) [ 316.183288] [<00000a0000226920>] do_tasklet+0x68/0xb0 (XEN) [ 316.189077] [<00000a000026e120>] domain.c#idle_loop+0x7c/0x194 (XEN) [ 316.195644] [<00000a0000277638>] shutdown.c#halt_this_cpu+0/0x14 (XEN) [ 316.202383] [<0000000000000008>] 0000000000000008 Freeing per-CPU areas and setting __per_cpu_offset to INVALID_PERCPU_AREA only occur when !park_offline_cpus and system_state is not SYS_STATE_suspend. On ARM64, park_offline_cpus is always false, so setting __per_cpu_offset to INVALID_PERCPU_AREA depends solely on the system state. If the system is suspended, this area is not freed, and during resume, an error occurs in init_percpu_area, causing a crash because INVALID_PERCPU_AREA is not set and park_offline_cpus remains 0: if ( __per_cpu_offset[cpu] != INVALID_PERCPU_AREA ) return park_offline_cpus ? 0 : -EBUSY; The same crash can occur on x86 if park_offline_cpus is set to 0 during Xen resume. Fixes: f75780d26b2f ("xen: move per-cpu area management into common code") Signed-off-by: Mykyta Poturai Signed-off-by: Mykola Kvach Reviewed-by: Jan Beulich --- Changes introduced in V3: - cosmetic fixes - change email in the "From:" tag Changes introduced in V2: - minor fixes after review - add "Fixes:" tag --- xen/common/percpu.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/xen/common/percpu.c b/xen/common/percpu.c index e4e8b7bcab..c6ecd95a08 100644 --- a/xen/common/percpu.c +++ b/xen/common/percpu.c @@ -30,7 +30,9 @@ static int init_percpu_area(unsigned int cpu) char *p; if ( __per_cpu_offset[cpu] != INVALID_PERCPU_AREA ) - return park_offline_cpus ? 0 : -EBUSY; + return park_offline_cpus || system_state == SYS_STATE_resume + ? 0 + : -EBUSY; if ( (p = alloc_xenheap_pages(PERCPU_ORDER, 0)) == NULL ) return -ENOMEM;