forked from Minki/linux
3a7d2fd16c
Lockdep complains about a possible deadlock between mount and unlink (which is technically impossible), but fixing this improves possible future multiple-backend support, and keeps locking in the right order. The lockdep warning could be triggered by unlinking a file in the pstore filesystem: -> #1 (&sb->s_type->i_mutex_key#14){++++++}: lock_acquire+0xc9/0x220 down_write+0x3f/0x70 pstore_mkfile+0x1f4/0x460 pstore_get_records+0x17a/0x320 pstore_fill_super+0xa4/0xc0 mount_single+0x89/0xb0 pstore_mount+0x13/0x20 mount_fs+0xf/0x90 vfs_kern_mount+0x66/0x170 do_mount+0x190/0xd50 SyS_mount+0x90/0xd0 entry_SYSCALL_64_fastpath+0x1c/0xb1 -> #0 (&psinfo->read_mutex){+.+.+.}: __lock_acquire+0x1ac0/0x1bb0 lock_acquire+0xc9/0x220 __mutex_lock+0x6e/0x990 mutex_lock_nested+0x16/0x20 pstore_unlink+0x3f/0xa0 vfs_unlink+0xb5/0x190 do_unlinkat+0x24c/0x2a0 SyS_unlinkat+0x16/0x30 entry_SYSCALL_64_fastpath+0x1c/0xb1 Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&sb->s_type->i_mutex_key#14); lock(&psinfo->read_mutex); lock(&sb->s_type->i_mutex_key#14); lock(&psinfo->read_mutex); Reported-by: Marta Lofstedt <marta.lofstedt@intel.com> Reported-by: Chris Wilson <chris@chris-wilson.co.uk> Signed-off-by: Kees Cook <keescook@chromium.org> Acked-by: Namhyung Kim <namhyung@kernel.org>
891 lines
20 KiB
C
891 lines
20 KiB
C
/*
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* Persistent Storage - platform driver interface parts.
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*
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* Copyright (C) 2007-2008 Google, Inc.
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* Copyright (C) 2010 Intel Corporation <tony.luck@intel.com>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*/
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#define pr_fmt(fmt) "pstore: " fmt
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#include <linux/atomic.h>
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#include <linux/types.h>
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#include <linux/errno.h>
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#include <linux/init.h>
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#include <linux/kmsg_dump.h>
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#include <linux/console.h>
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#include <linux/module.h>
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#include <linux/pstore.h>
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#ifdef CONFIG_PSTORE_ZLIB_COMPRESS
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#include <linux/zlib.h>
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#endif
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#ifdef CONFIG_PSTORE_LZO_COMPRESS
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#include <linux/lzo.h>
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#endif
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#ifdef CONFIG_PSTORE_LZ4_COMPRESS
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#include <linux/lz4.h>
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#endif
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#include <linux/string.h>
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#include <linux/timer.h>
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#include <linux/slab.h>
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#include <linux/uaccess.h>
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#include <linux/hardirq.h>
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#include <linux/jiffies.h>
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#include <linux/workqueue.h>
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#include "internal.h"
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/*
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* We defer making "oops" entries appear in pstore - see
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* whether the system is actually still running well enough
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* to let someone see the entry
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*/
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static int pstore_update_ms = -1;
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module_param_named(update_ms, pstore_update_ms, int, 0600);
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MODULE_PARM_DESC(update_ms, "milliseconds before pstore updates its content "
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"(default is -1, which means runtime updates are disabled; "
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"enabling this option is not safe, it may lead to further "
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"corruption on Oopses)");
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static int pstore_new_entry;
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static void pstore_timefunc(unsigned long);
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static DEFINE_TIMER(pstore_timer, pstore_timefunc, 0, 0);
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static void pstore_dowork(struct work_struct *);
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static DECLARE_WORK(pstore_work, pstore_dowork);
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/*
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* pstore_lock just protects "psinfo" during
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* calls to pstore_register()
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*/
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static DEFINE_SPINLOCK(pstore_lock);
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struct pstore_info *psinfo;
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static char *backend;
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/* Compression parameters */
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#ifdef CONFIG_PSTORE_ZLIB_COMPRESS
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#define COMPR_LEVEL 6
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#define WINDOW_BITS 12
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#define MEM_LEVEL 4
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static struct z_stream_s stream;
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#else
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static unsigned char *workspace;
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#endif
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struct pstore_zbackend {
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int (*compress)(const void *in, void *out, size_t inlen, size_t outlen);
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int (*decompress)(void *in, void *out, size_t inlen, size_t outlen);
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void (*allocate)(void);
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void (*free)(void);
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const char *name;
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};
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static char *big_oops_buf;
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static size_t big_oops_buf_sz;
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/* How much of the console log to snapshot */
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static unsigned long kmsg_bytes = 10240;
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void pstore_set_kmsg_bytes(int bytes)
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{
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kmsg_bytes = bytes;
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}
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/* Tag each group of saved records with a sequence number */
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static int oopscount;
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static const char *get_reason_str(enum kmsg_dump_reason reason)
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{
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switch (reason) {
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case KMSG_DUMP_PANIC:
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return "Panic";
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case KMSG_DUMP_OOPS:
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return "Oops";
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case KMSG_DUMP_EMERG:
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return "Emergency";
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case KMSG_DUMP_RESTART:
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return "Restart";
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case KMSG_DUMP_HALT:
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return "Halt";
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case KMSG_DUMP_POWEROFF:
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return "Poweroff";
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default:
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return "Unknown";
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}
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}
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bool pstore_cannot_block_path(enum kmsg_dump_reason reason)
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{
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/*
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* In case of NMI path, pstore shouldn't be blocked
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* regardless of reason.
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*/
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if (in_nmi())
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return true;
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switch (reason) {
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/* In panic case, other cpus are stopped by smp_send_stop(). */
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case KMSG_DUMP_PANIC:
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/* Emergency restart shouldn't be blocked by spin lock. */
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case KMSG_DUMP_EMERG:
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return true;
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default:
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return false;
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}
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}
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EXPORT_SYMBOL_GPL(pstore_cannot_block_path);
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#ifdef CONFIG_PSTORE_ZLIB_COMPRESS
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/* Derived from logfs_compress() */
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static int compress_zlib(const void *in, void *out, size_t inlen, size_t outlen)
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{
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int err, ret;
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ret = -EIO;
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err = zlib_deflateInit2(&stream, COMPR_LEVEL, Z_DEFLATED, WINDOW_BITS,
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MEM_LEVEL, Z_DEFAULT_STRATEGY);
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if (err != Z_OK)
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goto error;
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stream.next_in = in;
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stream.avail_in = inlen;
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stream.total_in = 0;
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stream.next_out = out;
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stream.avail_out = outlen;
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stream.total_out = 0;
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err = zlib_deflate(&stream, Z_FINISH);
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if (err != Z_STREAM_END)
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goto error;
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err = zlib_deflateEnd(&stream);
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if (err != Z_OK)
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goto error;
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if (stream.total_out >= stream.total_in)
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goto error;
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ret = stream.total_out;
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error:
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return ret;
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}
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/* Derived from logfs_uncompress */
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static int decompress_zlib(void *in, void *out, size_t inlen, size_t outlen)
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{
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int err, ret;
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ret = -EIO;
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err = zlib_inflateInit2(&stream, WINDOW_BITS);
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if (err != Z_OK)
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goto error;
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stream.next_in = in;
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stream.avail_in = inlen;
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stream.total_in = 0;
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stream.next_out = out;
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stream.avail_out = outlen;
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stream.total_out = 0;
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err = zlib_inflate(&stream, Z_FINISH);
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if (err != Z_STREAM_END)
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goto error;
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err = zlib_inflateEnd(&stream);
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if (err != Z_OK)
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goto error;
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ret = stream.total_out;
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error:
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return ret;
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}
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static void allocate_zlib(void)
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{
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size_t size;
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size_t cmpr;
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switch (psinfo->bufsize) {
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/* buffer range for efivars */
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case 1000 ... 2000:
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cmpr = 56;
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break;
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case 2001 ... 3000:
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cmpr = 54;
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break;
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case 3001 ... 3999:
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cmpr = 52;
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break;
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/* buffer range for nvram, erst */
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case 4000 ... 10000:
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cmpr = 45;
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break;
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default:
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cmpr = 60;
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break;
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}
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big_oops_buf_sz = (psinfo->bufsize * 100) / cmpr;
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big_oops_buf = kmalloc(big_oops_buf_sz, GFP_KERNEL);
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if (big_oops_buf) {
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size = max(zlib_deflate_workspacesize(WINDOW_BITS, MEM_LEVEL),
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zlib_inflate_workspacesize());
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stream.workspace = kmalloc(size, GFP_KERNEL);
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if (!stream.workspace) {
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pr_err("No memory for compression workspace; skipping compression\n");
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kfree(big_oops_buf);
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big_oops_buf = NULL;
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}
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} else {
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pr_err("No memory for uncompressed data; skipping compression\n");
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stream.workspace = NULL;
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}
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}
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static void free_zlib(void)
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{
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kfree(stream.workspace);
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stream.workspace = NULL;
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kfree(big_oops_buf);
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big_oops_buf = NULL;
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big_oops_buf_sz = 0;
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}
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static const struct pstore_zbackend backend_zlib = {
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.compress = compress_zlib,
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.decompress = decompress_zlib,
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.allocate = allocate_zlib,
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.free = free_zlib,
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.name = "zlib",
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};
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#endif
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#ifdef CONFIG_PSTORE_LZO_COMPRESS
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static int compress_lzo(const void *in, void *out, size_t inlen, size_t outlen)
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{
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int ret;
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ret = lzo1x_1_compress(in, inlen, out, &outlen, workspace);
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if (ret != LZO_E_OK) {
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pr_err("lzo_compress error, ret = %d!\n", ret);
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return -EIO;
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}
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return outlen;
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}
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static int decompress_lzo(void *in, void *out, size_t inlen, size_t outlen)
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{
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int ret;
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ret = lzo1x_decompress_safe(in, inlen, out, &outlen);
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if (ret != LZO_E_OK) {
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pr_err("lzo_decompress error, ret = %d!\n", ret);
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return -EIO;
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}
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return outlen;
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}
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static void allocate_lzo(void)
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{
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big_oops_buf_sz = lzo1x_worst_compress(psinfo->bufsize);
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big_oops_buf = kmalloc(big_oops_buf_sz, GFP_KERNEL);
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if (big_oops_buf) {
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workspace = kmalloc(LZO1X_MEM_COMPRESS, GFP_KERNEL);
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if (!workspace) {
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pr_err("No memory for compression workspace; skipping compression\n");
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kfree(big_oops_buf);
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big_oops_buf = NULL;
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}
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} else {
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pr_err("No memory for uncompressed data; skipping compression\n");
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workspace = NULL;
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}
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}
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static void free_lzo(void)
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{
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kfree(workspace);
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kfree(big_oops_buf);
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big_oops_buf = NULL;
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big_oops_buf_sz = 0;
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}
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static const struct pstore_zbackend backend_lzo = {
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.compress = compress_lzo,
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.decompress = decompress_lzo,
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.allocate = allocate_lzo,
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.free = free_lzo,
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.name = "lzo",
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};
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#endif
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#ifdef CONFIG_PSTORE_LZ4_COMPRESS
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static int compress_lz4(const void *in, void *out, size_t inlen, size_t outlen)
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{
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int ret;
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ret = LZ4_compress_default(in, out, inlen, outlen, workspace);
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if (!ret) {
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pr_err("LZ4_compress_default error; compression failed!\n");
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return -EIO;
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}
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return ret;
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}
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static int decompress_lz4(void *in, void *out, size_t inlen, size_t outlen)
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{
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int ret;
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ret = LZ4_decompress_safe(in, out, inlen, outlen);
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if (ret < 0) {
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/*
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* LZ4_decompress_safe will return an error code
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* (< 0) if decompression failed
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*/
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pr_err("LZ4_decompress_safe error, ret = %d!\n", ret);
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return -EIO;
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}
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return ret;
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}
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static void allocate_lz4(void)
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{
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big_oops_buf_sz = LZ4_compressBound(psinfo->bufsize);
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big_oops_buf = kmalloc(big_oops_buf_sz, GFP_KERNEL);
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if (big_oops_buf) {
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workspace = kmalloc(LZ4_MEM_COMPRESS, GFP_KERNEL);
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if (!workspace) {
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pr_err("No memory for compression workspace; skipping compression\n");
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kfree(big_oops_buf);
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big_oops_buf = NULL;
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}
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} else {
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pr_err("No memory for uncompressed data; skipping compression\n");
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workspace = NULL;
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}
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}
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static void free_lz4(void)
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{
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kfree(workspace);
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kfree(big_oops_buf);
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big_oops_buf = NULL;
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big_oops_buf_sz = 0;
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}
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static const struct pstore_zbackend backend_lz4 = {
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.compress = compress_lz4,
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.decompress = decompress_lz4,
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.allocate = allocate_lz4,
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.free = free_lz4,
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.name = "lz4",
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};
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#endif
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static const struct pstore_zbackend *zbackend =
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#if defined(CONFIG_PSTORE_ZLIB_COMPRESS)
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&backend_zlib;
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#elif defined(CONFIG_PSTORE_LZO_COMPRESS)
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&backend_lzo;
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#elif defined(CONFIG_PSTORE_LZ4_COMPRESS)
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&backend_lz4;
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#else
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NULL;
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#endif
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static int pstore_compress(const void *in, void *out,
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size_t inlen, size_t outlen)
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{
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if (zbackend)
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return zbackend->compress(in, out, inlen, outlen);
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else
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return -EIO;
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}
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static int pstore_decompress(void *in, void *out, size_t inlen, size_t outlen)
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{
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if (zbackend)
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return zbackend->decompress(in, out, inlen, outlen);
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else
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return -EIO;
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}
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static void allocate_buf_for_compression(void)
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{
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if (zbackend) {
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pr_info("using %s compression\n", zbackend->name);
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zbackend->allocate();
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} else {
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pr_err("allocate compression buffer error!\n");
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}
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}
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static void free_buf_for_compression(void)
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{
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if (zbackend)
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zbackend->free();
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else
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pr_err("free compression buffer error!\n");
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}
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/*
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* Called when compression fails, since the printk buffer
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* would be fetched for compression calling it again when
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* compression fails would have moved the iterator of
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* printk buffer which results in fetching old contents.
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* Copy the recent messages from big_oops_buf to psinfo->buf
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*/
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static size_t copy_kmsg_to_buffer(int hsize, size_t len)
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{
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size_t total_len;
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size_t diff;
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total_len = hsize + len;
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if (total_len > psinfo->bufsize) {
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diff = total_len - psinfo->bufsize + hsize;
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memcpy(psinfo->buf, big_oops_buf, hsize);
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memcpy(psinfo->buf + hsize, big_oops_buf + diff,
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psinfo->bufsize - hsize);
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total_len = psinfo->bufsize;
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} else
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memcpy(psinfo->buf, big_oops_buf, total_len);
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return total_len;
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}
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/*
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* callback from kmsg_dump. (s2,l2) has the most recently
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* written bytes, older bytes are in (s1,l1). Save as much
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* as we can from the end of the buffer.
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*/
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static void pstore_dump(struct kmsg_dumper *dumper,
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enum kmsg_dump_reason reason)
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{
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unsigned long total = 0;
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const char *why;
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unsigned int part = 1;
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unsigned long flags = 0;
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int is_locked;
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int ret;
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why = get_reason_str(reason);
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if (pstore_cannot_block_path(reason)) {
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is_locked = spin_trylock_irqsave(&psinfo->buf_lock, flags);
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if (!is_locked) {
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pr_err("pstore dump routine blocked in %s path, may corrupt error record\n"
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, in_nmi() ? "NMI" : why);
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return;
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}
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} else {
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spin_lock_irqsave(&psinfo->buf_lock, flags);
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is_locked = 1;
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}
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oopscount++;
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while (total < kmsg_bytes) {
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char *dst;
|
|
size_t dst_size;
|
|
int header_size;
|
|
int zipped_len = -1;
|
|
size_t dump_size;
|
|
struct pstore_record record = {
|
|
.type = PSTORE_TYPE_DMESG,
|
|
.count = oopscount,
|
|
.reason = reason,
|
|
.part = part,
|
|
.compressed = false,
|
|
.buf = psinfo->buf,
|
|
.psi = psinfo,
|
|
};
|
|
|
|
if (big_oops_buf && is_locked) {
|
|
dst = big_oops_buf;
|
|
dst_size = big_oops_buf_sz;
|
|
} else {
|
|
dst = psinfo->buf;
|
|
dst_size = psinfo->bufsize;
|
|
}
|
|
|
|
/* Write dump header. */
|
|
header_size = snprintf(dst, dst_size, "%s#%d Part%u\n", why,
|
|
oopscount, part);
|
|
dst_size -= header_size;
|
|
|
|
/* Write dump contents. */
|
|
if (!kmsg_dump_get_buffer(dumper, true, dst + header_size,
|
|
dst_size, &dump_size))
|
|
break;
|
|
|
|
if (big_oops_buf && is_locked) {
|
|
zipped_len = pstore_compress(dst, psinfo->buf,
|
|
header_size + dump_size,
|
|
psinfo->bufsize);
|
|
|
|
if (zipped_len > 0) {
|
|
record.compressed = true;
|
|
record.size = zipped_len;
|
|
} else {
|
|
record.size = copy_kmsg_to_buffer(header_size,
|
|
dump_size);
|
|
}
|
|
} else {
|
|
record.size = header_size + dump_size;
|
|
}
|
|
|
|
ret = psinfo->write(&record);
|
|
if (ret == 0 && reason == KMSG_DUMP_OOPS && pstore_is_mounted())
|
|
pstore_new_entry = 1;
|
|
|
|
total += record.size;
|
|
part++;
|
|
}
|
|
if (is_locked)
|
|
spin_unlock_irqrestore(&psinfo->buf_lock, flags);
|
|
}
|
|
|
|
static struct kmsg_dumper pstore_dumper = {
|
|
.dump = pstore_dump,
|
|
};
|
|
|
|
/*
|
|
* Register with kmsg_dump to save last part of console log on panic.
|
|
*/
|
|
static void pstore_register_kmsg(void)
|
|
{
|
|
kmsg_dump_register(&pstore_dumper);
|
|
}
|
|
|
|
static void pstore_unregister_kmsg(void)
|
|
{
|
|
kmsg_dump_unregister(&pstore_dumper);
|
|
}
|
|
|
|
#ifdef CONFIG_PSTORE_CONSOLE
|
|
static void pstore_console_write(struct console *con, const char *s, unsigned c)
|
|
{
|
|
const char *e = s + c;
|
|
|
|
while (s < e) {
|
|
struct pstore_record record = {
|
|
.type = PSTORE_TYPE_CONSOLE,
|
|
.psi = psinfo,
|
|
};
|
|
unsigned long flags;
|
|
|
|
if (c > psinfo->bufsize)
|
|
c = psinfo->bufsize;
|
|
|
|
if (oops_in_progress) {
|
|
if (!spin_trylock_irqsave(&psinfo->buf_lock, flags))
|
|
break;
|
|
} else {
|
|
spin_lock_irqsave(&psinfo->buf_lock, flags);
|
|
}
|
|
record.buf = (char *)s;
|
|
record.size = c;
|
|
psinfo->write(&record);
|
|
spin_unlock_irqrestore(&psinfo->buf_lock, flags);
|
|
s += c;
|
|
c = e - s;
|
|
}
|
|
}
|
|
|
|
static struct console pstore_console = {
|
|
.name = "pstore",
|
|
.write = pstore_console_write,
|
|
.flags = CON_PRINTBUFFER | CON_ENABLED | CON_ANYTIME,
|
|
.index = -1,
|
|
};
|
|
|
|
static void pstore_register_console(void)
|
|
{
|
|
register_console(&pstore_console);
|
|
}
|
|
|
|
static void pstore_unregister_console(void)
|
|
{
|
|
unregister_console(&pstore_console);
|
|
}
|
|
#else
|
|
static void pstore_register_console(void) {}
|
|
static void pstore_unregister_console(void) {}
|
|
#endif
|
|
|
|
static int pstore_write_user_compat(struct pstore_record *record,
|
|
const char __user *buf)
|
|
{
|
|
int ret = 0;
|
|
|
|
if (record->buf)
|
|
return -EINVAL;
|
|
|
|
record->buf = kmalloc(record->size, GFP_KERNEL);
|
|
if (!record->buf)
|
|
return -ENOMEM;
|
|
|
|
if (unlikely(copy_from_user(record->buf, buf, record->size))) {
|
|
ret = -EFAULT;
|
|
goto out;
|
|
}
|
|
|
|
ret = record->psi->write(record);
|
|
|
|
out:
|
|
kfree(record->buf);
|
|
record->buf = NULL;
|
|
|
|
return unlikely(ret < 0) ? ret : record->size;
|
|
}
|
|
|
|
/*
|
|
* platform specific persistent storage driver registers with
|
|
* us here. If pstore is already mounted, call the platform
|
|
* read function right away to populate the file system. If not
|
|
* then the pstore mount code will call us later to fill out
|
|
* the file system.
|
|
*/
|
|
int pstore_register(struct pstore_info *psi)
|
|
{
|
|
struct module *owner = psi->owner;
|
|
|
|
if (backend && strcmp(backend, psi->name)) {
|
|
pr_warn("ignoring unexpected backend '%s'\n", psi->name);
|
|
return -EPERM;
|
|
}
|
|
|
|
/* Sanity check flags. */
|
|
if (!psi->flags) {
|
|
pr_warn("backend '%s' must support at least one frontend\n",
|
|
psi->name);
|
|
return -EINVAL;
|
|
}
|
|
|
|
/* Check for required functions. */
|
|
if (!psi->read || !psi->write) {
|
|
pr_warn("backend '%s' must implement read() and write()\n",
|
|
psi->name);
|
|
return -EINVAL;
|
|
}
|
|
|
|
spin_lock(&pstore_lock);
|
|
if (psinfo) {
|
|
pr_warn("backend '%s' already loaded: ignoring '%s'\n",
|
|
psinfo->name, psi->name);
|
|
spin_unlock(&pstore_lock);
|
|
return -EBUSY;
|
|
}
|
|
|
|
if (!psi->write_user)
|
|
psi->write_user = pstore_write_user_compat;
|
|
psinfo = psi;
|
|
mutex_init(&psinfo->read_mutex);
|
|
spin_unlock(&pstore_lock);
|
|
|
|
if (owner && !try_module_get(owner)) {
|
|
psinfo = NULL;
|
|
return -EINVAL;
|
|
}
|
|
|
|
allocate_buf_for_compression();
|
|
|
|
if (pstore_is_mounted())
|
|
pstore_get_records(0);
|
|
|
|
if (psi->flags & PSTORE_FLAGS_DMESG)
|
|
pstore_register_kmsg();
|
|
if (psi->flags & PSTORE_FLAGS_CONSOLE)
|
|
pstore_register_console();
|
|
if (psi->flags & PSTORE_FLAGS_FTRACE)
|
|
pstore_register_ftrace();
|
|
if (psi->flags & PSTORE_FLAGS_PMSG)
|
|
pstore_register_pmsg();
|
|
|
|
/* Start watching for new records, if desired. */
|
|
if (pstore_update_ms >= 0) {
|
|
pstore_timer.expires = jiffies +
|
|
msecs_to_jiffies(pstore_update_ms);
|
|
add_timer(&pstore_timer);
|
|
}
|
|
|
|
/*
|
|
* Update the module parameter backend, so it is visible
|
|
* through /sys/module/pstore/parameters/backend
|
|
*/
|
|
backend = psi->name;
|
|
|
|
pr_info("Registered %s as persistent store backend\n", psi->name);
|
|
|
|
module_put(owner);
|
|
|
|
return 0;
|
|
}
|
|
EXPORT_SYMBOL_GPL(pstore_register);
|
|
|
|
void pstore_unregister(struct pstore_info *psi)
|
|
{
|
|
/* Stop timer and make sure all work has finished. */
|
|
pstore_update_ms = -1;
|
|
del_timer_sync(&pstore_timer);
|
|
flush_work(&pstore_work);
|
|
|
|
if (psi->flags & PSTORE_FLAGS_PMSG)
|
|
pstore_unregister_pmsg();
|
|
if (psi->flags & PSTORE_FLAGS_FTRACE)
|
|
pstore_unregister_ftrace();
|
|
if (psi->flags & PSTORE_FLAGS_CONSOLE)
|
|
pstore_unregister_console();
|
|
if (psi->flags & PSTORE_FLAGS_DMESG)
|
|
pstore_unregister_kmsg();
|
|
|
|
free_buf_for_compression();
|
|
|
|
psinfo = NULL;
|
|
backend = NULL;
|
|
}
|
|
EXPORT_SYMBOL_GPL(pstore_unregister);
|
|
|
|
static void decompress_record(struct pstore_record *record)
|
|
{
|
|
int unzipped_len;
|
|
char *decompressed;
|
|
|
|
/* Only PSTORE_TYPE_DMESG support compression. */
|
|
if (!record->compressed || record->type != PSTORE_TYPE_DMESG) {
|
|
pr_warn("ignored compressed record type %d\n", record->type);
|
|
return;
|
|
}
|
|
|
|
/* No compression method has created the common buffer. */
|
|
if (!big_oops_buf) {
|
|
pr_warn("no decompression buffer allocated\n");
|
|
return;
|
|
}
|
|
|
|
unzipped_len = pstore_decompress(record->buf, big_oops_buf,
|
|
record->size, big_oops_buf_sz);
|
|
if (unzipped_len <= 0) {
|
|
pr_err("decompression failed: %d\n", unzipped_len);
|
|
return;
|
|
}
|
|
|
|
/* Build new buffer for decompressed contents. */
|
|
decompressed = kmalloc(unzipped_len + record->ecc_notice_size,
|
|
GFP_KERNEL);
|
|
if (!decompressed) {
|
|
pr_err("decompression ran out of memory\n");
|
|
return;
|
|
}
|
|
memcpy(decompressed, big_oops_buf, unzipped_len);
|
|
|
|
/* Append ECC notice to decompressed buffer. */
|
|
memcpy(decompressed + unzipped_len, record->buf + record->size,
|
|
record->ecc_notice_size);
|
|
|
|
/* Swap out compresed contents with decompressed contents. */
|
|
kfree(record->buf);
|
|
record->buf = decompressed;
|
|
record->size = unzipped_len;
|
|
record->compressed = false;
|
|
}
|
|
|
|
/*
|
|
* Read all the records from one persistent store backend. Create
|
|
* files in our filesystem. Don't warn about -EEXIST errors
|
|
* when we are re-scanning the backing store looking to add new
|
|
* error records.
|
|
*/
|
|
void pstore_get_backend_records(struct pstore_info *psi,
|
|
struct dentry *root, int quiet)
|
|
{
|
|
int failed = 0;
|
|
|
|
if (!psi || !root)
|
|
return;
|
|
|
|
mutex_lock(&psi->read_mutex);
|
|
if (psi->open && psi->open(psi))
|
|
goto out;
|
|
|
|
/*
|
|
* Backend callback read() allocates record.buf. decompress_record()
|
|
* may reallocate record.buf. On success, pstore_mkfile() will keep
|
|
* the record.buf, so free it only on failure.
|
|
*/
|
|
for (;;) {
|
|
struct pstore_record *record;
|
|
int rc;
|
|
|
|
record = kzalloc(sizeof(*record), GFP_KERNEL);
|
|
if (!record) {
|
|
pr_err("out of memory creating record\n");
|
|
break;
|
|
}
|
|
record->psi = psi;
|
|
|
|
record->size = psi->read(record);
|
|
|
|
/* No more records left in backend? */
|
|
if (record->size <= 0)
|
|
break;
|
|
|
|
decompress_record(record);
|
|
rc = pstore_mkfile(root, record);
|
|
if (rc) {
|
|
/* pstore_mkfile() did not take record, so free it. */
|
|
kfree(record->buf);
|
|
kfree(record);
|
|
if (rc != -EEXIST || !quiet)
|
|
failed++;
|
|
}
|
|
}
|
|
if (psi->close)
|
|
psi->close(psi);
|
|
out:
|
|
mutex_unlock(&psi->read_mutex);
|
|
|
|
if (failed)
|
|
pr_warn("failed to load %d record(s) from '%s'\n",
|
|
failed, psi->name);
|
|
}
|
|
|
|
static void pstore_dowork(struct work_struct *work)
|
|
{
|
|
pstore_get_records(1);
|
|
}
|
|
|
|
static void pstore_timefunc(unsigned long dummy)
|
|
{
|
|
if (pstore_new_entry) {
|
|
pstore_new_entry = 0;
|
|
schedule_work(&pstore_work);
|
|
}
|
|
|
|
if (pstore_update_ms >= 0)
|
|
mod_timer(&pstore_timer,
|
|
jiffies + msecs_to_jiffies(pstore_update_ms));
|
|
}
|
|
|
|
module_param(backend, charp, 0444);
|
|
MODULE_PARM_DESC(backend, "Pstore backend to use");
|