From patchwork Tue Apr 14 11:32:20 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Vlastimil Babka X-Patchwork-Id: 11487279 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 2E7CB92C for ; Tue, 14 Apr 2020 11:32:38 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id EFB0B2072D for ; Tue, 14 Apr 2020 11:32:37 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org EFB0B2072D Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=suse.cz Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 8913E8E0006; Tue, 14 Apr 2020 07:32:31 -0400 (EDT) Delivered-To: linux-mm-outgoing@kvack.org Received: by kanga.kvack.org (Postfix, from userid 40) id 719218E0008; Tue, 14 Apr 2020 07:32:31 -0400 (EDT) X-Original-To: int-list-linux-mm@kvack.org X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 4CE4B8E0006; Tue, 14 Apr 2020 07:32:31 -0400 (EDT) X-Original-To: linux-mm@kvack.org X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0067.hostedemail.com [216.40.44.67]) by kanga.kvack.org (Postfix) with ESMTP id 1FCDA8E0001 for ; Tue, 14 Apr 2020 07:32:31 -0400 (EDT) Received: from smtpin20.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id CFDEC824559C for ; Tue, 14 Apr 2020 11:32:30 +0000 (UTC) X-FDA: 76706247660.20.hair14_8a4c6a39edd01 X-Spam-Summary: 1,0,0,,d41d8cd98f00b204,vbabka@suse.cz,,RULES_HIT:30029:30036:30054:30056:30062:30079,0,RBL:195.135.220.15:@suse.cz:.lbl8.mailshell.net-62.2.6.2 64.100.201.201,CacheIP:none,Bayesian:0.5,0.5,0.5,Netcheck:none,DomainCache:0,MSF:not bulk,SPF:fp,MSBL:0,DNSBL:neutral,Custom_rules:0:0:0,LFtime:25,LUA_SUMMARY:none X-HE-Tag: hair14_8a4c6a39edd01 X-Filterd-Recvd-Size: 9537 Received: from mx2.suse.de (mx2.suse.de [195.135.220.15]) by imf23.hostedemail.com (Postfix) with ESMTP for ; Tue, 14 Apr 2020 11:32:30 +0000 (UTC) X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx2.suse.de (Postfix) with ESMTP id 1F2ABAE63; Tue, 14 Apr 2020 11:32:27 +0000 (UTC) From: Vlastimil Babka To: Andrew Morton , Luis Chamberlain , Kees Cook , Iurii Zaikin Cc: linux-kernel@vger.kernel.org, linux-api@vger.kernel.org, linux-mm@kvack.org, Ivan Teterevkov , Michal Hocko , David Rientjes , Matthew Wilcox , "Eric W . Biederman" , "Guilherme G . Piccoli" , Alexey Dobriyan , Thomas Gleixner , Greg Kroah-Hartman , Christian Brauner , Masami Hiramatsu , Vlastimil Babka Subject: [PATCH v2 1/3] kernel/sysctl: support setting sysctl parameters from kernel command line Date: Tue, 14 Apr 2020 13:32:20 +0200 Message-Id: <20200414113222.16959-2-vbabka@suse.cz> X-Mailer: git-send-email 2.26.0 In-Reply-To: <20200414113222.16959-1-vbabka@suse.cz> References: <20200414113222.16959-1-vbabka@suse.cz> MIME-Version: 1.0 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: A recently proposed patch to add vm_swappiness command line parameter in addition to existing sysctl [1] made me wonder why we don't have a general support for passing sysctl parameters via command line. Googling found only somebody else wondering the same [2], but I haven't found any prior discussion with reasons why not to do this. Settings the vm_swappiness issue aside (the underlying issue might be solved in a different way), quick search of kernel-parameters.txt shows there are already some that exist as both sysctl and kernel parameter - hung_task_panic, nmi_watchdog, numa_zonelist_order, traceoff_on_warning. A general mechanism would remove the need to add more of those one-offs and might be handy in situations where configuration by e.g. /etc/sysctl.d/ is impractical. Hence, this patch adds a new parse_args() pass that looks for parameters prefixed by 'sysctl.' and tries to interpret them as writes to the corresponding sys/ files using an temporary in-kernel procfs mount. This mechanism was suggested by Eric W. Biederman [3], as it handles all dynamically registered sysctl tables, even though we don't handle modular sysctls. Errors due to e.g. invalid parameter name or value are reported in the kernel log. The processing is hooked right before the init process is loaded, as some handlers might be more complicated than simple setters and might need some subsystems to be initialized. At the moment the init process can be started and eventually execute a process writing to /proc/sys/ then it should be also fine to do that from the kernel. Sysctls registered later on module load time are not set by this mechanism - it's expected that in such scenarios, setting sysctl values from userspace is practical enough. [1] https://lore.kernel.org/r/BL0PR02MB560167492CA4094C91589930E9FC0@BL0PR02MB5601.namprd02.prod.outlook.com/ [2] https://unix.stackexchange.com/questions/558802/how-to-set-sysctl-using-kernel-command-line-parameter [3] https://lore.kernel.org/r/87bloj2skm.fsf@x220.int.ebiederm.org/ Signed-off-by: Vlastimil Babka Reviewed-by: Luis Chamberlain Acked-by: Kees Cook Reviewed-by: Masami Hiramatsu --- .../admin-guide/kernel-parameters.txt | 9 ++ fs/proc/proc_sysctl.c | 107 ++++++++++++++++++ include/linux/sysctl.h | 4 + init/main.c | 2 + 4 files changed, 122 insertions(+) diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index f2a93c8679e8..fd38f1e8a2bf 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -4891,6 +4891,15 @@ switches= [HW,M68k] + sysctl.*= [KNL] + Set a sysctl parameter, right before loading the init + process, as if the value was written to the respective + /proc/sys/... file. Both '.' and '/' are recognized as + separators. Unrecognized parameters and invalid values + are reported in the kernel log. Sysctls registered + later by a loaded module cannot be set this way. + Example: sysctl.vm.swappiness=40 + sysfs.deprecated=0|1 [KNL] Enable/disable old style sysfs layout for old udev on older distributions. When this option is enabled diff --git a/fs/proc/proc_sysctl.c b/fs/proc/proc_sysctl.c index b6f5d459b087..7804da5f5be0 100644 --- a/fs/proc/proc_sysctl.c +++ b/fs/proc/proc_sysctl.c @@ -14,6 +14,7 @@ #include #include #include +#include #include "internal.h" static const struct dentry_operations proc_sys_dentry_operations; @@ -1692,3 +1693,109 @@ int __init proc_sys_init(void) return sysctl_init(); } + +/* Set sysctl value passed on kernel command line. */ +static int process_sysctl_arg(char *param, char *val, + const char *unused, void *arg) +{ + char *path; + struct vfsmount **proc_mnt = arg; + struct file_system_type *proc_fs_type; + struct file *file; + int len; + int err; + loff_t pos = 0; + ssize_t wret; + + if (strncmp(param, "sysctl", sizeof("sysctl") - 1)) + return 0; + + param += sizeof("sysctl") - 1; + + if (param[0] != '/' && param[0] != '.') + return 0; + + param++; + + /* + * To set sysctl options, we use a temporary mount of proc, look up the + * respective sys/ file and write to it. To avoid mounting it when no + * options were given, we mount it only when the first sysctl option is + * found. Why not a persistent mount? There are problems with a + * persistent mount of proc in that it forces userspace not to use any + * proc mount options. + */ + if (!*proc_mnt) { + proc_fs_type = get_fs_type("proc"); + if (!proc_fs_type) { + pr_err("Failed to find procfs to set sysctl from command line\n"); + return 0; + } + *proc_mnt = kern_mount(proc_fs_type); + put_filesystem(proc_fs_type); + if (IS_ERR(*proc_mnt)) { + pr_err("Failed to mount procfs to set sysctl from command line\n"); + return 0; + } + } + + path = kasprintf(GFP_KERNEL, "sys/%s", param); + if (!path) + panic("%s: Failed to allocate path for %s\n", __func__, param); + strreplace(path, '.', '/'); + + file = file_open_root((*proc_mnt)->mnt_root, *proc_mnt, path, O_WRONLY, 0); + if (IS_ERR(file)) { + err = PTR_ERR(file); + if (err == -ENOENT) + pr_err("Failed to set sysctl parameter '%s=%s': parameter not found\n", + param, val); + else if (err == -EACCES) + pr_err("Failed to set sysctl parameter '%s=%s': permission denied (read-only?)\n", + param, val); + else + pr_err("Error %pe opening proc file to set sysctl parameter '%s=%s'\n", + file, param, val); + goto out; + } + len = strlen(val); + wret = kernel_write(file, val, len, &pos); + if (wret < 0) { + err = wret; + if (err == -EINVAL) + pr_err("Failed to set sysctl parameter '%s=%s': invalid value\n", + param, val); + else + pr_err("Error %pe writing to proc file to set sysctl parameter '%s=%s'\n", + ERR_PTR(err), param, val); + } else if (wret != len) { + pr_err("Wrote only %zd bytes of %d writing to proc file %s to set sysctl parameter '%s=%s\n", + wret, len, path, param, val); + } + + err = filp_close(file, NULL); + if (err) + pr_err("Error %pe closing proc file to set sysctl parameter '%s=%s\n", + ERR_PTR(err), param, val); +out: + kfree(path); + return 0; +} + +void do_sysctl_args(void) +{ + char *command_line; + struct vfsmount *proc_mnt = NULL; + + command_line = kstrdup(saved_command_line, GFP_KERNEL); + if (!command_line) + panic("%s: Failed to allocate copy of command line\n", __func__); + + parse_args("Setting sysctl args", command_line, + NULL, 0, -1, -1, &proc_mnt, process_sysctl_arg); + + if (proc_mnt) + kern_unmount(proc_mnt); + + kfree(command_line); +} diff --git a/include/linux/sysctl.h b/include/linux/sysctl.h index 02fa84493f23..bee62d30ebdb 100644 --- a/include/linux/sysctl.h +++ b/include/linux/sysctl.h @@ -206,6 +206,7 @@ struct ctl_table_header *register_sysctl_paths(const struct ctl_path *path, void unregister_sysctl_table(struct ctl_table_header * table); extern int sysctl_init(void); +void do_sysctl_args(void); extern struct ctl_table sysctl_mount_point[]; @@ -236,6 +237,9 @@ static inline void setup_sysctl_set(struct ctl_table_set *p, { } +static inline void do_sysctl_args(void) +{ +} #endif /* CONFIG_SYSCTL */ int sysctl_max_threads(struct ctl_table *table, int write, diff --git a/init/main.c b/init/main.c index a48617f2e5e5..7b43118215d6 100644 --- a/init/main.c +++ b/init/main.c @@ -1372,6 +1372,8 @@ static int __ref kernel_init(void *unused) rcu_end_inkernel_boot(); + do_sysctl_args(); + if (ramdisk_execute_command) { ret = run_init_process(ramdisk_execute_command); if (!ret) From patchwork Tue Apr 14 11:32:21 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Vlastimil Babka X-Patchwork-Id: 11487275 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id D893D912 for ; Tue, 14 Apr 2020 11:32:33 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id AF38A2072D for ; Tue, 14 Apr 2020 11:32:33 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org AF38A2072D Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=suse.cz Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 3565E8E0005; Tue, 14 Apr 2020 07:32:31 -0400 (EDT) Delivered-To: linux-mm-outgoing@kvack.org Received: by kanga.kvack.org (Postfix, from userid 40) id 088A88E0008; Tue, 14 Apr 2020 07:32:31 -0400 (EDT) X-Original-To: int-list-linux-mm@kvack.org X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id DF8698E0001; Tue, 14 Apr 2020 07:32:30 -0400 (EDT) X-Original-To: linux-mm@kvack.org X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0033.hostedemail.com [216.40.44.33]) by kanga.kvack.org (Postfix) with ESMTP id C46FF8E0006 for ; Tue, 14 Apr 2020 07:32:30 -0400 (EDT) Received: from smtpin27.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id 7CE928245571 for ; Tue, 14 Apr 2020 11:32:30 +0000 (UTC) X-FDA: 76706247660.27.ducks51_8a410cfc1261d X-Spam-Summary: 1,0,0,,d41d8cd98f00b204,vbabka@suse.cz,,RULES_HIT:30029:30030:30054:30062,0,RBL:195.135.220.15:@suse.cz:.lbl8.mailshell.net-62.2.6.2 64.100.201.201,CacheIP:none,Bayesian:0.5,0.5,0.5,Netcheck:none,DomainCache:0,MSF:not bulk,SPF:fp,MSBL:0,DNSBL:neutral,Custom_rules:0:0:0,LFtime:25,LUA_SUMMARY:none X-HE-Tag: ducks51_8a410cfc1261d X-Filterd-Recvd-Size: 4928 Received: from mx2.suse.de (mx2.suse.de [195.135.220.15]) by imf37.hostedemail.com (Postfix) with ESMTP for ; Tue, 14 Apr 2020 11:32:29 +0000 (UTC) X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx2.suse.de (Postfix) with ESMTP id 36D2DAE9A; Tue, 14 Apr 2020 11:32:27 +0000 (UTC) From: Vlastimil Babka To: Andrew Morton , Luis Chamberlain , Kees Cook , Iurii Zaikin Cc: linux-kernel@vger.kernel.org, linux-api@vger.kernel.org, linux-mm@kvack.org, Ivan Teterevkov , Michal Hocko , David Rientjes , Matthew Wilcox , "Eric W . Biederman" , "Guilherme G . Piccoli" , Alexey Dobriyan , Thomas Gleixner , Greg Kroah-Hartman , Christian Brauner , Masami Hiramatsu , Vlastimil Babka Subject: [PATCH v2 2/3] kernel/sysctl: support handling command line aliases Date: Tue, 14 Apr 2020 13:32:21 +0200 Message-Id: <20200414113222.16959-3-vbabka@suse.cz> X-Mailer: git-send-email 2.26.0 In-Reply-To: <20200414113222.16959-1-vbabka@suse.cz> References: <20200414113222.16959-1-vbabka@suse.cz> MIME-Version: 1.0 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: We can now handle sysctl parameters on kernel command line, but historically some parameters introduced their own command line equivalent, which we don't want to remove for compatibility reasons. We can however convert them to the generic infrastructure with a table translating the legacy command line parameters to their sysctl names, and removing the one-off param handlers. This patch adds the support and makes the first conversion to demonstrate it, on the (deprecated) numa_zonelist_order parameter. Signed-off-by: Vlastimil Babka Acked-by: Kees Cook Reviewed-by: Luis Chamberlain --- fs/proc/proc_sysctl.c | 48 ++++++++++++++++++++++++++++++++++++------- mm/page_alloc.c | 9 -------- 2 files changed, 41 insertions(+), 16 deletions(-) diff --git a/fs/proc/proc_sysctl.c b/fs/proc/proc_sysctl.c index 7804da5f5be0..209ad03e1b82 100644 --- a/fs/proc/proc_sysctl.c +++ b/fs/proc/proc_sysctl.c @@ -1694,6 +1694,37 @@ int __init proc_sys_init(void) return sysctl_init(); } +struct sysctl_alias { + const char *kernel_param; + const char *sysctl_param; +}; + +/* + * Historically some settings had both sysctl and a command line parameter. + * With the generic sysctl. parameter support, we can handle them at a single + * place and only keep the historical name for compatibility. This is not meant + * to add brand new aliases. When adding existing aliases, consider whether + * the possibly different moment of changing the value (e.g. from early_param + * to the moment do_sysctl_args() is called) is an issue for the specific + * parameter. + */ +static const struct sysctl_alias sysctl_aliases[] = { + {"numa_zonelist_order", "vm.numa_zonelist_order" }, + { } +}; + +static const char *sysctl_find_alias(char *param) +{ + const struct sysctl_alias *alias; + + for (alias = &sysctl_aliases[0]; alias->kernel_param != NULL; alias++) { + if (strcmp(alias->kernel_param, param) == 0) + return alias->sysctl_param; + } + + return NULL; +} + /* Set sysctl value passed on kernel command line. */ static int process_sysctl_arg(char *param, char *val, const char *unused, void *arg) @@ -1707,15 +1738,18 @@ static int process_sysctl_arg(char *param, char *val, loff_t pos = 0; ssize_t wret; - if (strncmp(param, "sysctl", sizeof("sysctl") - 1)) - return 0; - - param += sizeof("sysctl") - 1; + if (strncmp(param, "sysctl", sizeof("sysctl") - 1) == 0) { + param += sizeof("sysctl") - 1; - if (param[0] != '/' && param[0] != '.') - return 0; + if (param[0] != '/' && param[0] != '.') + return 0; - param++; + param++; + } else { + param = (char *) sysctl_find_alias(param); + if (!param) + return 0; + } /* * To set sysctl options, we use a temporary mount of proc, look up the diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 69827d4fa052..80b2788711c9 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -5531,15 +5531,6 @@ static int __parse_numa_zonelist_order(char *s) return 0; } -static __init int setup_numa_zonelist_order(char *s) -{ - if (!s) - return 0; - - return __parse_numa_zonelist_order(s); -} -early_param("numa_zonelist_order", setup_numa_zonelist_order); - char numa_zonelist_order[] = "Node"; /* From patchwork Tue Apr 14 11:32:22 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Vlastimil Babka X-Patchwork-Id: 11487273 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 779EA912 for ; Tue, 14 Apr 2020 11:32:32 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 4D21A206D5 for ; Tue, 14 Apr 2020 11:32:31 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 4D21A206D5 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=suse.cz Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 08E668E000A; Tue, 14 Apr 2020 07:32:31 -0400 (EDT) Delivered-To: linux-mm-outgoing@kvack.org Received: by kanga.kvack.org (Postfix, from userid 40) id 0125C8E0005; Tue, 14 Apr 2020 07:32:30 -0400 (EDT) X-Original-To: int-list-linux-mm@kvack.org X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id D58B68E0008; Tue, 14 Apr 2020 07:32:30 -0400 (EDT) X-Original-To: linux-mm@kvack.org X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0210.hostedemail.com [216.40.44.210]) by kanga.kvack.org (Postfix) with ESMTP id B8B958E0001 for ; Tue, 14 Apr 2020 07:32:30 -0400 (EDT) Received: from smtpin26.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with ESMTP id 862261269 for ; Tue, 14 Apr 2020 11:32:30 +0000 (UTC) X-FDA: 76706247660.26.crate18_8a458e03c6e1e X-Spam-Summary: 1,0,0,,d41d8cd98f00b204,vbabka@suse.cz,,RULES_HIT:30054:30062,0,RBL:195.135.220.15:@suse.cz:.lbl8.mailshell.net-62.2.6.2 64.100.201.201,CacheIP:none,Bayesian:0.5,0.5,0.5,Netcheck:none,DomainCache:0,MSF:not bulk,SPF:fp,MSBL:0,DNSBL:neutral,Custom_rules:0:0:0,LFtime:25,LUA_SUMMARY:none X-HE-Tag: crate18_8a458e03c6e1e X-Filterd-Recvd-Size: 4001 Received: from mx2.suse.de (mx2.suse.de [195.135.220.15]) by imf19.hostedemail.com (Postfix) with ESMTP for ; Tue, 14 Apr 2020 11:32:30 +0000 (UTC) X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx2.suse.de (Postfix) with ESMTP id 80E37AEC3; Tue, 14 Apr 2020 11:32:27 +0000 (UTC) From: Vlastimil Babka To: Andrew Morton , Luis Chamberlain , Kees Cook , Iurii Zaikin Cc: linux-kernel@vger.kernel.org, linux-api@vger.kernel.org, linux-mm@kvack.org, Ivan Teterevkov , Michal Hocko , David Rientjes , Matthew Wilcox , "Eric W . Biederman" , "Guilherme G . Piccoli" , Alexey Dobriyan , Thomas Gleixner , Greg Kroah-Hartman , Christian Brauner , Masami Hiramatsu , Vlastimil Babka Subject: [PATCH v2 3/3] kernel/hung_task convert hung_task_panic boot parameter to sysctl Date: Tue, 14 Apr 2020 13:32:22 +0200 Message-Id: <20200414113222.16959-4-vbabka@suse.cz> X-Mailer: git-send-email 2.26.0 In-Reply-To: <20200414113222.16959-1-vbabka@suse.cz> References: <20200414113222.16959-1-vbabka@suse.cz> MIME-Version: 1.0 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: We can now handle sysctl parameters on kernel command line and have infrastructure to convert legacy command line options that duplicate sysctl to become a sysctl alias. This patch converts the hung_task_panic parameter. Note that the sysctl handler is more strict and allows only 0 and 1, while the legacy parameter allowed any non-zero value. But there is little reason anyone would not be using 1. Signed-off-by: Vlastimil Babka Reviewed-by: Kees Cook --- Documentation/admin-guide/kernel-parameters.txt | 2 +- fs/proc/proc_sysctl.c | 1 + kernel/hung_task.c | 10 ---------- 3 files changed, 2 insertions(+), 11 deletions(-) diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index fd38f1e8a2bf..e60478d9d377 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -1491,7 +1491,7 @@ [KNL] Should the hung task detector generate panics. Format: - A nonzero value instructs the kernel to panic when a + A value of 1 instructs the kernel to panic when a hung task is detected. The default value is controlled by the CONFIG_BOOTPARAM_HUNG_TASK_PANIC build-time option. The value selected by this boot parameter can diff --git a/fs/proc/proc_sysctl.c b/fs/proc/proc_sysctl.c index 209ad03e1b82..e8f97bd65909 100644 --- a/fs/proc/proc_sysctl.c +++ b/fs/proc/proc_sysctl.c @@ -1710,6 +1710,7 @@ struct sysctl_alias { */ static const struct sysctl_alias sysctl_aliases[] = { {"numa_zonelist_order", "vm.numa_zonelist_order" }, + {"hung_task_panic", "kernel.hung_task_panic" }, { } }; diff --git a/kernel/hung_task.c b/kernel/hung_task.c index 14a625c16cb3..b22b5eeab3cb 100644 --- a/kernel/hung_task.c +++ b/kernel/hung_task.c @@ -63,16 +63,6 @@ static struct task_struct *watchdog_task; unsigned int __read_mostly sysctl_hung_task_panic = CONFIG_BOOTPARAM_HUNG_TASK_PANIC_VALUE; -static int __init hung_task_panic_setup(char *str) -{ - int rc = kstrtouint(str, 0, &sysctl_hung_task_panic); - - if (rc) - return rc; - return 1; -} -__setup("hung_task_panic=", hung_task_panic_setup); - static int hung_task_panic(struct notifier_block *this, unsigned long event, void *ptr) {