From: Linus Torvalds <torvalds@linux-foundation.org>
Date: Fri, 30 Nov 2018 17:03:15 +0000 (-0800)
Subject: Merge tag 'pstore-v4.20-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/kees... 
X-Git-Tag: v4.20-rc5~27
X-Git-Url: https://git.kernel.dk/?a=commitdiff_plain;h=e9eaf72e73d6159afbf90a9a02c24f2099067992;hp=-c;p=linux-block.git

Merge tag 'pstore-v4.20-rc5' of git://git./linux/kernel/git/kees/linux

Pull pstore fix from Kees Cook:
 "Fix corrupted compression due to unlucky size choice with ECC"

* tag 'pstore-v4.20-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
  pstore/ram: Correctly calculate usable PRZ bytes
---

e9eaf72e73d6159afbf90a9a02c24f2099067992
diff --combined fs/pstore/ram.c
index ffcff6516e89,8646fe6e916f..e02a9039b5ea
--- a/fs/pstore/ram.c
+++ b/fs/pstore/ram.c
@@@ -816,17 -816,14 +816,14 @@@ static int ramoops_probe(struct platfor
  
  	cxt->pstore.data = cxt;
  	/*
- 	 * Console can handle any buffer size, so prefer LOG_LINE_MAX. If we
- 	 * have to handle dumps, we must have at least record_size buffer. And
- 	 * for ftrace, bufsize is irrelevant (if bufsize is 0, buf will be
- 	 * ZERO_SIZE_PTR).
+ 	 * Since bufsize is only used for dmesg crash dumps, it
+ 	 * must match the size of the dprz record (after PRZ header
+ 	 * and ECC bytes have been accounted for).
  	 */
- 	if (cxt->console_size)
- 		cxt->pstore.bufsize = 1024; /* LOG_LINE_MAX */
- 	cxt->pstore.bufsize = max(cxt->record_size, cxt->pstore.bufsize);
- 	cxt->pstore.buf = kmalloc(cxt->pstore.bufsize, GFP_KERNEL);
+ 	cxt->pstore.bufsize = cxt->dprzs[0]->buffer_size;
+ 	cxt->pstore.buf = kzalloc(cxt->pstore.bufsize, GFP_KERNEL);
  	if (!cxt->pstore.buf) {
- 		pr_err("cannot allocate pstore buffer\n");
+ 		pr_err("cannot allocate pstore crash dump buffer\n");
  		err = -ENOMEM;
  		goto fail_clear;
  	}
@@@ -908,22 -905,8 +905,22 @@@ static struct platform_driver ramoops_d
  	},
  };
  
 -static void ramoops_register_dummy(void)
 +static inline void ramoops_unregister_dummy(void)
  {
 +	platform_device_unregister(dummy);
 +	dummy = NULL;
 +
 +	kfree(dummy_data);
 +	dummy_data = NULL;
 +}
 +
 +static void __init ramoops_register_dummy(void)
 +{
 +	/*
 +	 * Prepare a dummy platform data structure to carry the module
 +	 * parameters. If mem_size isn't set, then there are no module
 +	 * parameters, and we can skip this.
 +	 */
  	if (!mem_size)
  		return;
  
@@@ -956,28 -939,21 +953,28 @@@
  	if (IS_ERR(dummy)) {
  		pr_info("could not create platform device: %ld\n",
  			PTR_ERR(dummy));
 +		dummy = NULL;
 +		ramoops_unregister_dummy();
  	}
  }
  
  static int __init ramoops_init(void)
  {
 +	int ret;
 +
  	ramoops_register_dummy();
 -	return platform_driver_register(&ramoops_driver);
 +	ret = platform_driver_register(&ramoops_driver);
 +	if (ret != 0)
 +		ramoops_unregister_dummy();
 +
 +	return ret;
  }
  postcore_initcall(ramoops_init);
  
  static void __exit ramoops_exit(void)
  {
  	platform_driver_unregister(&ramoops_driver);
 -	platform_device_unregister(dummy);
 -	kfree(dummy_data);
 +	ramoops_unregister_dummy();
  }
  module_exit(ramoops_exit);