Received: by 2002:a05:6a10:5bc5:0:0:0:0 with SMTP id os5csp5096468pxb; Thu, 14 Oct 2021 19:18:33 -0700 (PDT) X-Google-Smtp-Source: ABdhPJwTg8QwzPzU7WtRuALx5Q/ESc6v1YYtPgzMBix5V/JTAqRGskjaTzsCMsgG1qL+gJ/FnqL6 X-Received: by 2002:a17:902:6f17:b0:139:eec4:867e with SMTP id w23-20020a1709026f1700b00139eec4867emr8534028plk.77.1634264313518; Thu, 14 Oct 2021 19:18:33 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1634264313; cv=none; d=google.com; s=arc-20160816; b=ZWOqC2iXYuHGJ5xhEkwarbrAvlRRoAn9IFFcuN4BHGw6a28C3/mgXCPrz4vVjjoRQw hIRPgxnU6CAtVXCT1YDsXB3+DPlW5qxlKdMKXo0der1p/+d+CUPKLseSa7TLwEVu3fGr Z8pwqn3ew6J1gEsBWd8BDJo/dXi2LpMDMHNkA0VDi9rAW3Sig8ZY5u/g9s9anxmSEZsZ CBBKjEaUJ7N1qhQA6oS5JbaOGGs3sFDF9IvkA8qsfPUkAtt1BzV0aDGNF2el5qkkEHO+ PdqklACjjOGQSmfST39q8nw3nJPKev1f4BJA0E+AK3SpUYlmEyg1XUj3nNDC2dMqszjU yUvA== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:sender:in-reply-to:content-disposition :mime-version:references:message-id:subject:cc:to:from:date :dkim-signature; bh=H/+saBVHG6Q0/3w93ZreMAu3RniGzEFHzOX/deXs7WM=; b=JoSBhTSQIAQGnXKx8FXGKo5Ei5uPOQJ1AOyPDlL6Q1zSiP0q90vCuGwsM89cmsUfbz 2zPVZQUXGpepQVzNbFB0smsxYKDb6h520Zlfbv4APlcv07OhQ+WyEba87no6cf+1jF7g rbNOJfpFtFbPKYSwFIQ+P1ZY8Gpk4uNVy9YP6ABs3ZvlAb18/grhDnIjXM/bzzD5L5xH eO6ONuPkE+rZ+2sPdx547L1/c229+iSZlwJ/hohxzMT3xdmxLtSIY9D77v1i7532pQc8 V1fwEk+QqQXFon4yormtWUezvbkgE5OzMM//gabn6A8jl5QE+0IJVhfSIjdGMcgCJQwI VoEw== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@infradead.org header.s=bombadil.20210309 header.b="moxm7Ky/"; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=kernel.org Return-Path: Received: from vger.kernel.org (vger.kernel.org. [23.128.96.18]) by mx.google.com with ESMTP id s15si5384595plq.364.2021.10.14.19.18.19; Thu, 14 Oct 2021 19:18:33 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18; Authentication-Results: mx.google.com; dkim=pass header.i=@infradead.org header.s=bombadil.20210309 header.b="moxm7Ky/"; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231286AbhJNU0r (ORCPT + 99 others); Thu, 14 Oct 2021 16:26:47 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36770 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229637AbhJNU0q (ORCPT ); Thu, 14 Oct 2021 16:26:46 -0400 Received: from bombadil.infradead.org (unknown [IPv6:2607:7c80:54:e::133]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id DA8B4C061570; Thu, 14 Oct 2021 13:24:41 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20210309; h=Sender:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=H/+saBVHG6Q0/3w93ZreMAu3RniGzEFHzOX/deXs7WM=; b=moxm7Ky/KkaxZMIX+sDuPRs9SX a6kbxyFuHrfxo8f2Y2/l7Hh4u6J1z1pdV7r9x1a4ZR2OAHn2zc5tQIfEWV6yhP8lxOrFLmJ7uslKr SDbIVJ2jJ0JDVFRciyb5WOC4w0yIM+HqfRcPh2kL1orbm9OTkjzA3igI0RuhXnj2xMLxthcXA713f BCLrie7TmS8R9NLD439hSLPp8jtoSJGNnO5wkAz6j7uxxEUMhzyf5VH1DFvx3ISYBzOQqMkxbQAxr AVRXPp6fHhdE8Hj/QB3Y4DhMQlJYHo9zviV9vJ3a1/Qhy/tF+bRqTbsH0wBVrv4saIf5H6GE/Sec9 yxeQSZDw==; Received: from mcgrof by bombadil.infradead.org with local (Exim 4.94.2 #2 (Red Hat Linux)) id 1mb7HE-004Lo0-4q; Thu, 14 Oct 2021 20:24:32 +0000 Date: Thu, 14 Oct 2021 13:24:32 -0700 From: Luis Chamberlain To: Ming Lei Cc: tj@kernel.org, gregkh@linuxfoundation.org, akpm@linux-foundation.org, minchan@kernel.org, jeyu@kernel.org, shuah@kernel.org, bvanassche@acm.org, dan.j.williams@intel.com, joe@perches.com, tglx@linutronix.de, keescook@chromium.org, rostedt@goodmis.org, linux-spdx@vger.kernel.org, linux-doc@vger.kernel.org, linux-block@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v8 11/12] zram: fix crashes with cpu hotplug multistate Message-ID: References: <20210927163805.808907-1-mcgrof@kernel.org> <20210927163805.808907-12-mcgrof@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: Luis Chamberlain Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Oct 14, 2021 at 10:11:46AM +0800, Ming Lei wrote: > On Thu, Oct 14, 2021 at 09:55:48AM +0800, Ming Lei wrote: > > On Mon, Sep 27, 2021 at 09:38:04AM -0700, Luis Chamberlain wrote: > > ... > > > > > Hello Luis, > > > > Can you test the following patch and see if the issue can be addressed? > > > > Please see the idea from the inline comment. > > > > Also zram_index_mutex isn't needed in zram disk's store() compared with > > your patch, then the deadlock issue you are addressing in this series can > > be avoided. > > > > > > diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c > > index fcaf2750f68f..3c17927d23a7 100644 > > --- a/drivers/block/zram/zram_drv.c > > +++ b/drivers/block/zram/zram_drv.c > > @@ -1985,11 +1985,17 @@ static int zram_remove(struct zram *zram) > > > > /* Make sure all the pending I/O are finished */ > > fsync_bdev(bdev); > > - zram_reset_device(zram); > > > > pr_info("Removed device: %s\n", zram->disk->disk_name); > > > > del_gendisk(zram->disk); > > + > > + /* > > + * reset device after gendisk is removed, so any change from sysfs > > + * store won't come in, then we can really reset device here > > + */ > > + zram_reset_device(zram); > > + > > blk_cleanup_disk(zram->disk); > > kfree(zram); > > return 0; > > @@ -2073,7 +2079,12 @@ static int zram_remove_cb(int id, void *ptr, void *data) > > static void destroy_devices(void) > > { > > class_unregister(&zram_control_class); > > + > > + /* hold the global lock so new device can't be added */ > > + mutex_lock(&zram_index_mutex); > > idr_for_each(&zram_index_idr, &zram_remove_cb, NULL); > > + mutex_unlock(&zram_index_mutex); > > + > > Actually zram_index_mutex isn't needed when calling zram_remove_cb() > since the zram-control sysfs interface has been removed, so userspace > can't add new device any more, then the issue is supposed to be fixed > by the following one line change, please test it: > > diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c > index fcaf2750f68f..96dd641de233 100644 > --- a/drivers/block/zram/zram_drv.c > +++ b/drivers/block/zram/zram_drv.c > @@ -1985,11 +1985,17 @@ static int zram_remove(struct zram *zram) > > /* Make sure all the pending I/O are finished */ > fsync_bdev(bdev); > - zram_reset_device(zram); > > pr_info("Removed device: %s\n", zram->disk->disk_name); > > del_gendisk(zram->disk); > + > + /* > + * reset device after gendisk is removed, so any change from sysfs > + * store won't come in, then we can really reset device here > + */ > + zram_reset_device(zram); > + > blk_cleanup_disk(zram->disk); > kfree(zram); > return 0; Sorry but nope, the cpu multistate issue is still present and we end up eventually with page faults. I tried with both patches. Oct 14 20:21:34 kdevops kernel: ------------[ cut here ]------------ Oct 14 20:21:34 kdevops kernel: Error: Removing state 65 which has instances left. Oct 14 20:21:34 kdevops kernel: WARNING: CPU: 4 PID: 3358 at kernel/cpu.c:2151 __cpuhp_remove_state_cpuslocked+0xf9/0x100 Oct 14 20:21:34 kdevops kernel: Modules linked in: zram(E-) zstd(E) zsmalloc(E) kvm_intel(E) kvm(E) irqbypass(E) crct10dif_pclmul(E) crc32_pclmul(E) ghash_clmulni_intel(E) > Oct 14 20:21:34 kdevops kernel: CPU: 4 PID: 3358 Comm: rmmod Tainted: G E 5.15.0-rc3-next-20210927+ #89 Oct 14 20:21:34 kdevops kernel: Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.14.0-2 04/01/2014 Oct 14 20:21:34 kdevops kernel: RIP: 0010:__cpuhp_remove_state_cpuslocked+0xf9/0x100 Oct 14 20:21:34 kdevops kernel: Code: 21 00 48 c7 43 18 00 00 00 00 5b 5d 41 5c 41 5d 41 5e 41 5f e9 d8 17 84 00 0f 0b 44 89 e6 48 c7 c7 78 0c 8b ad e8 56 92 7f 00 <0f> 0b > Oct 14 20:21:34 kdevops kernel: RSP: 0018:ffffaac980a1fe90 EFLAGS: 00010286 Oct 14 20:21:34 kdevops kernel: RAX: 0000000000000000 RBX: ffffffffada3e208 RCX: 0000000000000000 Oct 14 20:21:34 kdevops kernel: RDX: 0000000000000001 RSI: ffffffffad8efdb6 RDI: 00000000ffffffff Oct 14 20:21:34 kdevops kernel: RBP: 0000000000000000 R08: 0000000000000000 R09: ffffaac980a1fcc0 Oct 14 20:21:34 kdevops kernel: R10: ffffaac980a1fcb8 R11: ffffffffadac3c68 R12: 0000000000000041 Oct 14 20:21:34 kdevops kernel: R13: 0000000000000a28 R14: 0000000000000000 R15: 0000000000000000 Oct 14 20:21:34 kdevops kernel: FS: 00007fc0c2882580(0000) GS:ffff9ed6f7d00000(0000) knlGS:0000000000000000 Oct 14 20:21:34 kdevops kernel: CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 Oct 14 20:21:34 kdevops kernel: CR2: 00005621b0490b78 CR3: 000000011a538005 CR4: 0000000000370ee0 Oct 14 20:21:34 kdevops kernel: DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 Oct 14 20:21:34 kdevops kernel: DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Oct 14 20:21:34 kdevops kernel: Call Trace: Oct 14 20:21:34 kdevops kernel: Oct 14 20:21:34 kdevops kernel: __cpuhp_remove_state+0x4d/0xc0 Oct 14 20:21:34 kdevops kernel: __do_sys_delete_module+0x18d/0x2a0 Oct 14 20:21:34 kdevops kernel: ? fpregs_assert_state_consistent+0x1e/0x40 Oct 14 20:21:34 kdevops kernel: ? exit_to_user_mode_prepare+0x3a/0x180 Oct 14 20:21:34 kdevops kernel: do_syscall_64+0x38/0xc0 Oct 14 20:21:34 kdevops kernel: entry_SYSCALL_64_after_hwframe+0x44/0xae Oct 14 20:21:34 kdevops kernel: RIP: 0033:0x7fc0c29a84a7 Oct 14 20:21:35 kdevops kernel: sysfs: cannot create duplicate filename '/devices/virtual/block/zram0' Oct 14 20:21:35 kdevops kernel: CPU: 5 PID: 3388 Comm: modprobe Tainted: G W E 5.15.0-rc3-next-20210927+ #89 Oct 14 20:21:35 kdevops kernel: Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.14.0-2 04/01/2014 Oct 14 20:21:35 kdevops kernel: Call Trace: Oct 14 20:21:35 kdevops kernel: Oct 14 20:21:35 kdevops kernel: dump_stack_lvl+0x48/0x5e Oct 14 20:21:35 kdevops kernel: sysfs_warn_dup.cold+0x17/0x24 Oct 14 20:21:35 kdevops kernel: sysfs_create_dir_ns+0xbc/0xd0 Oct 14 20:21:35 kdevops kernel: kobject_add_internal+0xbd/0x2b0 Oct 14 20:21:35 kdevops kernel: kobject_add+0x7e/0xb0 Oct 14 20:21:35 kdevops kernel: ? _raw_spin_unlock_irqrestore+0x25/0x40 Oct 14 20:21:35 kdevops kernel: ? preempt_count_add+0x68/0xa0 Oct 14 20:21:35 kdevops kernel: device_add+0x11a/0x980 Oct 14 20:21:35 kdevops kernel: ? dev_set_name+0x53/0x70 Oct 14 20:21:35 kdevops kernel: device_add_disk+0x9d/0x3a0 Oct 14 20:21:35 kdevops kernel: zram_add+0x1ad/0x200 [zram] Oct 14 20:21:35 kdevops kernel: ? 0xffffffffc0c10000 Oct 14 20:21:35 kdevops kernel: zram_init+0xd7/0x1000 [zram] Oct 14 20:21:35 kdevops kernel: do_one_initcall+0x41/0x200 Oct 14 20:21:35 kdevops kernel: ? _raw_spin_unlock_irqrestore+0x25/0x40 Oct 14 20:21:35 kdevops kernel: ? kmem_cache_alloc_trace+0x2ab/0x420 Oct 14 20:21:35 kdevops kernel: do_init_module+0x5c/0x270 Oct 14 20:21:35 kdevops kernel: __do_sys_finit_module+0xae/0x110 Oct 14 20:21:35 kdevops kernel: do_syscall_64+0x38/0xc0 Oct 14 20:21:35 kdevops kernel: entry_SYSCALL_64_after_hwframe+0x44/0xae Oct 14 20:21:35 kdevops kernel: RIP: 0033:0x7fca3aa555e9 Oct 14 20:21:35 kdevops kernel: Code: 00 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d > Oct 14 20:21:35 kdevops kernel: RSP: 002b:00007fff142417b8 EFLAGS: 00000246 ORIG_RAX: 0000000000000139 Oct 14 20:21:35 kdevops kernel: RAX: ffffffffffffffda RBX: 0000558ba9491bd0 RCX: 00007fca3aa555e9 Oct 14 20:21:35 kdevops kernel: RDX: 0000000000000000 RSI: 0000558ba9491f60 RDI: 0000000000000003 Oct 14 20:21:35 kdevops kernel: RBP: 0000000000040000 R08: 0000000000000000 R09: 0000558ba9491db0 Oct 14 20:21:35 kdevops kernel: R10: 0000000000000003 R11: 0000000000000246 R12: 0000558ba9491f60 Oct 14 20:21:35 kdevops kernel: R13: 0000000000000000 R14: 0000558ba9491d00 R15: 0000558ba9491bd0 Oct 14 20:21:35 kdevops kernel: Oct 14 20:21:35 kdevops kernel: kobject_add_internal failed for zram0 with -EEXIST, don't try to register things with the same name in the same directory. Oct 14 20:21:35 kdevops kernel: ------------[ cut here ]------------ Oct 14 20:21:35 kdevops kernel: WARNING: CPU: 5 PID: 3388 at block/genhd.c:537 device_add_disk+0x1b9/0x3a0 Oct 14 20:21:35 kdevops kernel: Modules linked in: zram(E+) zstd(E) zsmalloc(E) kvm_intel(E) kvm(E) irqbypass(E) crct10dif_pclmul(E) crc32_pclmul(E) ghash_clmulni_intel(E) > Oct 14 20:21:35 kdevops kernel: CPU: 5 PID: 3388 Comm: modprobe Tainted: G W E 5.15.0-rc3-next-20210927+ #89 Oct 14 20:21:35 kdevops kernel: Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.14.0-2 04/01/2014 Oct 14 20:21:35 kdevops kernel: RIP: 0010:device_add_disk+0x1b9/0x3a0 Oct 14 20:21:35 kdevops kernel: Code: 00 03 01 00 00 0f 85 32 ff ff ff e9 1e ff ff ff 0f 0b 41 bc ea ff ff ff e9 29 ff ff ff 4c 89 ff e8 5c 45 1c 00 e9 ef fe ff ff <0f> 0b > Oct 14 20:21:35 kdevops kernel: RSP: 0018:ffffaac980607d90 EFLAGS: 00010287 Oct 14 20:21:35 kdevops kernel: RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000023005 Oct 14 20:21:35 kdevops kernel: RDX: 0000000000022e05 RSI: ffffffffacc4b710 RDI: 0000000000000000 Oct 14 20:21:35 kdevops kernel: RBP: ffff9ed5d788a600 R08: 0000000000000000 R09: ffffaac980607a98 Oct 14 20:21:35 kdevops kernel: R10: ffff9ed5c795ef00 R11: ffffffffadac3c68 R12: 00000000ffffffef Oct 14 20:21:35 kdevops kernel: R13: ffff9ed5d5600000 R14: ffffffffc0a52100 R15: ffff9ed5d5600040 Oct 14 20:21:35 kdevops kernel: FS: 00007fca3a935580(0000) GS:ffff9ed6f7d40000(0000) knlGS:0000000000000000 Oct 14 20:21:35 kdevops kernel: CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 Oct 14 20:21:35 kdevops kernel: CR2: 00007fff1423e6d8 CR3: 0000000136752002 CR4: 0000000000370ee0 Oct 14 20:21:35 kdevops kernel: DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 Oct 14 20:21:35 kdevops kernel: DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Oct 14 20:21:35 kdevops kernel: Call Trace: Oct 14 20:21:35 kdevops kernel: Oct 14 20:21:35 kdevops kernel: zram_add+0x1ad/0x200 [zram] Oct 14 20:21:35 kdevops kernel: ? 0xffffffffc0c10000 Oct 14 20:21:35 kdevops kernel: zram_init+0xd7/0x1000 [zram] Oct 14 20:21:35 kdevops kernel: do_one_initcall+0x41/0x200 Oct 14 20:21:35 kdevops kernel: ? _raw_spin_unlock_irqrestore+0x25/0x40 Oct 14 20:21:35 kdevops kernel: ? kmem_cache_alloc_trace+0x2ab/0x420 Oct 14 20:21:35 kdevops kernel: do_init_module+0x5c/0x270 Oct 14 20:21:35 kdevops kernel: __do_sys_finit_module+0xae/0x110 Oct 14 20:21:35 kdevops kernel: do_syscall_64+0x38/0xc0 Oct 14 20:21:35 kdevops kernel: entry_SYSCALL_64_after_hwframe+0x44/0xae Oct 14 20:21:35 kdevops kernel: RIP: 0033:0x7fca3aa555e9 Oct 14 20:21:35 kdevops kernel: ------------[ cut here ]------------ Oct 14 20:21:35 kdevops kernel: WARNING: CPU: 2 PID: 3457 at block/genhd.c:564 del_gendisk+0x1a2/0x1d0 Oct 14 20:21:35 kdevops kernel: Modules linked in: 842(E) 842_decompress(E) 842_compress(E) zram(E-) zstd(E) zsmalloc(E) kvm_intel(E) kvm(E) irqbypass(E) crct10dif_pclmul(E> Oct 14 20:21:35 kdevops kernel: CPU: 2 PID: 3457 Comm: rmmod Tainted: G W E 5.15.0-rc3-next-20210927+ #89 Oct 14 20:21:35 kdevops kernel: Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.14.0-2 04/01/2014 Oct 14 20:21:35 kdevops kernel: RIP: 0010:del_gendisk+0x1a2/0x1d0 Oct 14 20:21:35 kdevops kernel: Code: 48 8d 78 40 e8 8f 87 1d 00 48 8b 7b 40 5b 5d 41 5c 48 83 c7 40 e9 4e 47 1c 00 48 8b 70 40 eb ce f6 43 61 04 0f 85 85 fe ff ff <0f> 0b > Oct 14 20:21:35 kdevops kernel: RSP: 0018:ffffaac9807cfe30 EFLAGS: 00010246 Oct 14 20:21:35 kdevops kernel: RAX: ffff9ed5d5600380 RBX: ffff9ed5d788a600 RCX: 0000000000000000 Oct 14 20:21:35 kdevops kernel: RDX: 0000000000000000 RSI: ffffffffad8efdb6 RDI: ffff9ed5d788a600 Oct 14 20:21:35 kdevops kernel: RBP: ffff9ed5d788b600 R08: 0000000000000000 R09: ffffaac9807cfc88 Oct 14 20:21:35 kdevops kernel: R10: ffffaac9807cfc80 R11: ffffffffadac3c68 R12: ffff9ed5d5600000 Oct 14 20:21:35 kdevops kernel: R13: 0000000000000000 R14: ffffffffc0a52360 R15: ffff9ed5c4a87b78 Oct 14 20:21:35 kdevops kernel: FS: 00007f292a2bb580(0000) GS:ffff9ed6f7c80000(0000) knlGS:0000000000000000 Oct 14 20:21:35 kdevops kernel: CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 Oct 14 20:21:35 kdevops kernel: CR2: 000056161b453b78 CR3: 000000013213e002 CR4: 0000000000370ee0 Oct 14 20:21:35 kdevops kernel: DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 Oct 14 20:21:35 kdevops kernel: DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Oct 14 20:21:35 kdevops kernel: Call Trace: Oct 14 20:21:35 kdevops kernel: Oct 14 20:21:35 kdevops kernel: zram_remove+0x96/0xc0 [zram] Oct 14 20:21:35 kdevops kernel: ? hot_remove_store+0xe0/0xe0 [zram] Oct 14 20:21:35 kdevops kernel: zram_remove_cb+0xd/0x10 [zram] Oct 14 20:21:35 kdevops kernel: idr_for_each+0x5b/0xd0 Oct 14 20:21:35 kdevops kernel: destroy_devices+0x32/0x68 [zram] Oct 14 20:21:35 kdevops kernel: __do_sys_delete_module+0x18d/0x2a0 Oct 14 20:21:35 kdevops kernel: ? fpregs_assert_state_consistent+0x1e/0x40 Oct 14 20:21:35 kdevops kernel: ? exit_to_user_mode_prepare+0x3a/0x180 Oct 14 20:21:35 kdevops kernel: do_syscall_64+0x38/0xc0 Oct 14 20:21:35 kdevops kernel: entry_SYSCALL_64_after_hwframe+0x44/0xae Oct 14 20:21:35 kdevops kernel: RIP: 0033:0x7f292a3e14a7 Oct 14 20:21:35 kdevops kernel: BUG: unable to handle page fault for address: ffffffffc0a4e0ae Oct 14 20:21:35 kdevops kernel: #PF: supervisor instruction fetch in kernel mode Oct 14 20:21:35 kdevops kernel: #PF: error_code(0x0010) - not-present page Oct 14 20:21:35 kdevops kernel: PGD 3ba0e067 P4D 3ba0e067 PUD 3ba10067 PMD 10526c067 PTE 0 Oct 14 20:21:35 kdevops kernel: Oops: 0010 [#1] PREEMPT SMP NOPTI Oct 14 20:21:35 kdevops kernel: CPU: 6 PID: 3655 Comm: zram02.sh Tainted: G W E 5.15.0-rc3-next-20210927+ #89 Oct 14 20:21:35 kdevops kernel: Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.14.0-2 04/01/2014 Oct 14 20:21:35 kdevops kernel: RIP: 0010:0xffffffffc0a4e0ae Oct 14 20:21:35 kdevops kernel: Code: Unable to access opcode bytes at RIP 0xffffffffc0a4e084. Oct 14 20:21:35 kdevops kernel: RSP: 0018:ffffaac980687da8 EFLAGS: 00010286 Oct 14 20:21:35 kdevops kernel: RAX: 0000000000000000 RBX: ffff9ed5c40be400 RCX: 0000000080400035 Oct 14 20:21:35 kdevops kernel: RDX: 0000000080400036 RSI: fffffa3544561080 RDI: 0000000040000000 Oct 14 20:21:35 kdevops kernel: RBP: 0000000001900000 R08: ffff9ed5d5842cc0 R09: 0000000080400035 Oct 14 20:21:35 kdevops kernel: R10: ffff9ed5d5842c00 R11: ffff9ed5f1341350 R12: 0000000001900000 Oct 14 20:21:35 kdevops kernel: R13: ffff9ed5d5666c00 R14: ffff9ed5c40be420 R15: ffff9ed5dfa8c8c0 Oct 14 20:21:35 kdevops kernel: FS: 00007f978fe2d5c0(0000) GS:ffff9ed6f7d80000(0000) knlGS:0000000000000000 Oct 14 20:21:35 kdevops kernel: CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 Oct 14 20:21:35 kdevops kernel: CR2: ffffffffc0a4e084 CR3: 0000000133fd4006 CR4: 0000000000370ee0 Oct 14 20:21:35 kdevops kernel: DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 Oct 14 20:21:35 kdevops kernel: DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Oct 14 20:21:35 kdevops kernel: Call Trace: Oct 14 20:21:35 kdevops kernel: Oct 14 20:21:35 kdevops kernel: ? kernfs_fop_write_iter+0x177/0x220 Oct 14 20:21:35 kdevops kernel: ? new_sync_write+0x11c/0x1b0 Oct 14 20:21:35 kdevops kernel: ? vfs_write+0x20d/0x2a0 Oct 14 20:21:35 kdevops kernel: ? ksys_write+0x5f/0xe0 Oct 14 20:21:35 kdevops kernel: ? do_syscall_64+0x38/0xc0 Oct 14 20:21:35 kdevops kernel: ? entry_SYSCALL_64_after_hwframe+0x44/0xae Oct 14 20:21:35 kdevops kernel: Luis