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([95.67.15.120]) by smtp.gmail.com with ESMTPSA id a640c23a62f3a-ac3efb64a2asm1229031066b.92.2025.03.27.04.32.39 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 27 Mar 2025 04:32:40 -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: 320021db-0aff-11f0-9ea3-5ba50f476ded DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1743075161; x=1743679961; 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=SiEaN7cfNVNuO5q9MKTZb30f+X3rKu30S9/vPJL/aWM=; b=M5jDdzX8A+E08JhdWQtuYpJxst1rF5Ca0we69+eUX5WYIAjDNW7xcmLlC6DQaKdNtj HR2TjyYi7wpK6Ecc2UEQ92GU5KQA9donh9khstSiiDB/K1uRwPDGuxRtn5TpKSKsc9vX 4J0teKMdS3P5rOeKq1xovCMB2JgsrC0VscAPsTJPhDy/9hkWizu6HDns/eqrCXWC62u/ x0HWu2FEk1WGXHBJa/2Q8n6WHDvDgdELjaHrXzWOH+13KbipPSJSl8g7AgNqzi8GMH0p SnxNiaVM98tKaXXR0116yUDypDo9q0FGNoy2pGmaHDQphsjpLgXRil/+kdK78LaFkXdy sHWQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1743075161; x=1743679961; 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=SiEaN7cfNVNuO5q9MKTZb30f+X3rKu30S9/vPJL/aWM=; b=SEl9rEWd+J8TzRiJigLinTWzqHXGVhpkRc47vpK/hqEevaSca9ZPpsCvQivJTaNab+ L57W0c8ADkWPq+sxEYSLURhJ4CviFU/spdCVPwdJ8EU3X0Fd124PhGEh0M6yodozwpv1 oQjiKyY8KrrAjpbTDzeiuQYrqiqHm4FxfmNbTiqTMilZDtPwzkaiS2mpmCf74j82nNm0 FVTO+56XN7SXx1AyX/3mYpZxzswBtW95YIaO/9LuEMgUayVzQzb13LYZE1PLwlaieqgj 7gNxq4zx7agYQb9Br5KrhV9LWVIpVUBvdBwT5X35w4C2dctPcU049Oml+C5uEinHJ16M Qnpw== X-Gm-Message-State: AOJu0Yy+dGWIQre0x+rlmIbej6VxOLfdkxP4INA9OUeA3uRQ8l3kgFQe O2S62+4okSudonCB3WFxkxzdbyZPPaSxXqe5DvDoKRNeSIqn9F0ABFybGg== X-Gm-Gg: ASbGncsrWCBJdaZjBO20MkLfDX6cbJdrZ294DxWdIEwi/709Lkw6+jGbQp3y+pFJdHV MLmqIdKGDsZTVJ3bhPa9CbbFU5mCj1zHGfaATiNXvjZP8mEFP5pLr9zEUNXMlrDVN9f6zWHf/xV DHrBTkQH5yTwnfdPsCJ5CSg4BfwUbKusmQxWTJPVAwsQ8brQeFZ+gjKqZNNjfGktzAsQ1Y5Atle f3gRJZyceh4y3c8MHryaz0NWz9ETq2h90Hh4cnwIRBn2XsvKg9LtX/w3KCHvudpU7vzWdtBAlvW /frWb65wfEI2k0js3C6sGVgoLOSZU1dOaKC0BtnfEzg6MqdONKc2iGnKamXuKR1JFmW0oD32C58 +PvC9slAB X-Google-Smtp-Source: AGHT+IG3V5Tr1egLTLnhtRk+Ob11D/SkbQlTGWvilIgAaiaHGTcghuBbYfROmo7OMaQ0JIuDra+hwg== X-Received: by 2002:a17:907:3d92:b0:ac3:c7c6:3c97 with SMTP id a640c23a62f3a-ac6fa7e7335mr285968166b.0.1743075160370; Thu, 27 Mar 2025 04:32:40 -0700 (PDT) From: Mykola Kvach To: xen-devel@lists.xenproject.org Cc: Mykola Kvach , Andrew Cooper , Anthony PERARD , Michal Orzel , Jan Beulich , Julien Grall , =?utf-8?q?Roger_Pau_Monn=C3=A9?= , Stefano Stabellini , Mykyta Poturai Subject: [PATCH v2] xen/percpu: don't initialize percpu on resume Date: Thu, 27 Mar 2025 13:32:25 +0200 Message-ID: <7c3fece57a28462ae0c071c1cf72eb32541f1b91.1743074241.git.mykola_kvach@epam.com> X-Mailer: git-send-email 2.43.0 MIME-Version: 1.0 From: Mykola Kvach 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 V2: - cosmetic fixes after review - chnages in a commit message: add "Fixes" --- 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..b20f0460fc 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;