Re: [PATCH v2 05/11] pstore/blk: blkoops: support ftrace recorder

From: Kees Cook
Date: Wed Mar 18 2020 - 14:19:23 EST

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On Fri, Feb 07, 2020 at 08:25:49PM +0800, WeiXiong Liao wrote:
> Support recorder for ftrace. To enable ftrace recorder, just make
> ftrace_size be greater than 0 and a multiple of 4096.
>
> Signed-off-by: WeiXiong Liao <liaoweixiong@xxxxxxxxxxxxxxxxx>
> ---
> fs/pstore/Kconfig | 12 ++++++++
> fs/pstore/blkoops.c | 11 +++++++
> fs/pstore/blkzone.c | 75 ++++++++++++++++++++++++++++++++++++++++++++--
> include/linux/pstore_blk.h | 4 +++
> 4 files changed, 99 insertions(+), 3 deletions(-)
>
> diff --git a/fs/pstore/Kconfig b/fs/pstore/Kconfig
> index 5f0a42823028..308a0a4c5ee5 100644
> --- a/fs/pstore/Kconfig
> +++ b/fs/pstore/Kconfig
> @@ -210,6 +210,18 @@ config PSTORE_BLKOOPS_CONSOLE_SIZE
> NOTE that, both kconfig and module parameters can configure blkoops,
> but module parameters have priority over kconfig.
>
> +config PSTORE_BLKOOPS_FTRACE_SIZE
> + int "ftrace size in kbytes for blkoops"
> + depends on PSTORE_BLKOOPS
> + depends on PSTORE_FTRACE
> + default 64

Same tricks. :)

> + help
> + This just sets size of ftrace (ftrace_size) for pstore/blk. The
> + size is in KB and must be a multiple of 4.
> +
> + NOTE that, both kconfig and module parameters can configure blkoops,
> + but module parameters have priority over kconfig.
> +
> config PSTORE_BLKOOPS_BLKDEV
> string "block device for blkoops"
> depends on PSTORE_BLKOOPS
> diff --git a/fs/pstore/blkoops.c b/fs/pstore/blkoops.c
> index 05990bc3b168..c76bab671b0b 100644
> --- a/fs/pstore/blkoops.c
> +++ b/fs/pstore/blkoops.c
> @@ -24,6 +24,10 @@
> module_param(console_size, long, 0400);
> MODULE_PARM_DESC(console_size, "console size in kbytes");
>
> +static long ftrace_size = -1;
> +module_param(ftrace_size, long, 0400);
> +MODULE_PARM_DESC(ftrace_size, "ftrace size in kbytes");
> +
> static int dump_oops = -1;
> module_param(dump_oops, int, 0400);
> MODULE_PARM_DESC(total_size, "whether dump oops");
> @@ -80,6 +84,12 @@
> #define DEFAULT_CONSOLE_SIZE 0
> #endif
>
> +#ifdef CONFIG_PSTORE_BLKOOPS_FTRACE_SIZE
> +#define DEFAULT_FTRACE_SIZE CONFIG_PSTORE_BLKOOPS_FTRACE_SIZE
> +#else
> +#define DEFAULT_FTRACE_SIZE 0
> +#endif
> +
> #ifdef CONFIG_PSTORE_BLKOOPS_DUMP_OOPS
> #define DEFAULT_DUMP_OOPS CONFIG_PSTORE_BLKOOPS_DUMP_OOPS
> #else
> @@ -135,6 +145,7 @@ int blkoops_register_device(struct blkoops_device *bo_dev)
> verify_size(dmesg_size, DEFAULT_DMESG_SIZE, 4096);
> verify_size(pmsg_size, DEFAULT_PMSG_SIZE, 4096);
> verify_size(console_size, DEFAULT_CONSOLE_SIZE, 4096);
> + verify_size(ftrace_size, DEFAULT_FTRACE_SIZE, 4096);
> #undef verify_size
> dump_oops = !!(dump_oops < 0 ? DEFAULT_DUMP_OOPS : dump_oops);
>
> diff --git a/fs/pstore/blkzone.c b/fs/pstore/blkzone.c
> index 9a7e9b06ccf7..442e5a5bbfda 100644
> --- a/fs/pstore/blkzone.c
> +++ b/fs/pstore/blkzone.c
> @@ -89,10 +89,13 @@ struct blkz_context {
> struct blkz_zone **dbzs; /* dmesg block zones */
> struct blkz_zone *pbz; /* Pmsg block zone */
> struct blkz_zone *cbz; /* console block zone */
> + struct blkz_zone **fbzs; /* Ftrace zones */
> unsigned int dmesg_max_cnt;
> unsigned int dmesg_read_cnt;
> unsigned int pmsg_read_cnt;
> unsigned int console_read_cnt;
> + unsigned int ftrace_max_cnt;
> + unsigned int ftrace_read_cnt;
> unsigned int dmesg_write_cnt;
> /*
> * the counter should be recovered when recover.
> @@ -281,6 +284,7 @@ static void blkz_flush_all_dirty_zones(struct work_struct *work)
> blkz_flush_dirty_zone(cxt->pbz);
> blkz_flush_dirty_zone(cxt->cbz);
> blkz_flush_dirty_zones(cxt->dbzs, cxt->dmesg_max_cnt);
> + blkz_flush_dirty_zones(cxt->fbzs, cxt->ftrace_max_cnt);
> }
>
> static int blkz_recover_dmesg_data(struct blkz_context *cxt)
> @@ -497,6 +501,31 @@ static int blkz_recover_zone(struct blkz_context *cxt, struct blkz_zone *zone)
> return ret;
> }
>
> +static int blkz_recover_zones(struct blkz_context *cxt,
> + struct blkz_zone **zones, unsigned int cnt)
> +{
> + int ret;
> + unsigned int i;
> + struct blkz_zone *zone;
> +
> + if (!zones)
> + return 0;
> +
> + for (i = 0; i < cnt; i++) {
> + zone = zones[i];
> + if (unlikely(!zone))
> + continue;
> + ret = blkz_recover_zone(cxt, zone);
> + if (ret)
> + goto recover_fail;
> + }
> +
> + return 0;
> +recover_fail:
> + pr_debug("recover %s[%u] failed\n", zone->name, i);
> + return ret;
> +}

Why is this introduced here? Shouldn't this be earlier in the series?

> +
> static inline int blkz_recovery(struct blkz_context *cxt)
> {
> int ret = -EBUSY;
> @@ -516,6 +545,10 @@ static inline int blkz_recovery(struct blkz_context *cxt)
> if (ret)
> goto recover_fail;
>
> + ret = blkz_recover_zones(cxt, cxt->fbzs, cxt->ftrace_max_cnt);
> + if (ret)
> + goto recover_fail;
> +
> pr_debug("recover end!\n");
> atomic_set(&cxt->recovered, 1);
> return 0;
> @@ -532,6 +565,7 @@ static int blkz_pstore_open(struct pstore_info *psi)
> cxt->dmesg_read_cnt = 0;
> cxt->pmsg_read_cnt = 0;
> cxt->console_read_cnt = 0;
> + cxt->ftrace_read_cnt = 0;
> return 0;
> }
>
> @@ -589,6 +623,8 @@ static int blkz_pstore_erase(struct pstore_record *record)
> return blkz_record_erase(cxt, cxt->pbz);
> case PSTORE_TYPE_CONSOLE:
> return blkz_record_erase(cxt, cxt->cbz);
> + case PSTORE_TYPE_FTRACE:
> + return blkz_record_erase(cxt, cxt->fbzs[record->id]);
> default: return -EINVAL;
> }
> }
> @@ -743,6 +779,13 @@ static int notrace blkz_pstore_write(struct pstore_record *record)
> return blkz_record_write(cxt, cxt->cbz, record);
> case PSTORE_TYPE_PMSG:
> return blkz_record_write(cxt, cxt->pbz, record);
> + case PSTORE_TYPE_FTRACE: {
> + int zonenum = smp_processor_id();
> +
> + if (!cxt->fbzs)
> + return -ENOSPC;
> + return blkz_record_write(cxt, cxt->fbzs[zonenum], record);
> + }
> default:
> return -EINVAL;
> }
> @@ -759,6 +802,12 @@ static struct blkz_zone *blkz_read_next_zone(struct blkz_context *cxt)
> return zone;
> }
>
> + while (cxt->ftrace_read_cnt < cxt->ftrace_max_cnt) {
> + zone = cxt->fbzs[cxt->ftrace_read_cnt++];
> + if (blkz_old_ok(zone))
> + return zone;
> + }
> +
> if (cxt->pmsg_read_cnt == 0) {
> cxt->pmsg_read_cnt++;
> zone = cxt->pbz;
> @@ -881,6 +930,9 @@ static ssize_t blkz_pstore_read(struct pstore_record *record)
> readop = blkz_dmesg_read;
> record->id = cxt->dmesg_read_cnt - 1;
> break;
> + case PSTORE_TYPE_FTRACE:
> + record->id = cxt->ftrace_read_cnt - 1;
> + /* fallthrough */

Please mark with "fallthrough;".
https://www.kernel.org/doc/html/latest/process/deprecated.html#implicit-switch-case-fall-through

> case PSTORE_TYPE_CONSOLE:
> /* fallthrough */
> case PSTORE_TYPE_PMSG:
> @@ -1046,15 +1098,27 @@ static int blkz_cut_zones(struct blkz_context *cxt)
> goto free_pmsg;
> }
>
> + off_size += info->ftrace_size;
> + cxt->fbzs = blkz_init_zones(PSTORE_TYPE_FTRACE, &off,
> + info->ftrace_size,
> + info->ftrace_size / nr_cpu_ids,
> + &cxt->ftrace_max_cnt);
> + if (IS_ERR(cxt->fbzs)) {
> + err = PTR_ERR(cxt->fbzs);
> + goto free_console;
> + }
> +
> cxt->dbzs = blkz_init_zones(PSTORE_TYPE_DMESG, &off,
> info->total_size - off_size,
> info->dmesg_size, &cxt->dmesg_max_cnt);
> if (IS_ERR(cxt->dbzs)) {
> err = PTR_ERR(cxt->dbzs);
> - goto free_console;
> + goto free_ftrace;
> }
>
> return 0;
> +free_ftrace:
> + blkz_free_zones(&cxt->fbzs, &cxt->ftrace_max_cnt);
> free_console:
> blkz_free_zone(&cxt->cbz);
> free_pmsg:
> @@ -1103,6 +1167,7 @@ int blkz_register(struct blkz_info *info)
> check_size(dmesg_size, SECTOR_SIZE);
> check_size(pmsg_size, SECTOR_SIZE);
> check_size(console_size, SECTOR_SIZE);
> + check_size(ftrace_size, SECTOR_SIZE);
>
> #undef check_size
>
> @@ -1136,6 +1201,7 @@ int blkz_register(struct blkz_info *info)
> pr_debug("\tdmesg size : %ld Bytes\n", info->dmesg_size);
> pr_debug("\tpmsg size : %ld Bytes\n", info->pmsg_size);
> pr_debug("\tconsole size : %ld Bytes\n", info->console_size);
> + pr_debug("\tftrace size : %ld Bytes\n", info->ftrace_size);
>
> err = blkz_cut_zones(cxt);
> if (err) {
> @@ -1159,13 +1225,16 @@ int blkz_register(struct blkz_info *info)
> cxt->pstore.flags |= PSTORE_FLAGS_PMSG;
> if (info->console_size)
> cxt->pstore.flags |= PSTORE_FLAGS_CONSOLE;
> + if (info->ftrace_size)
> + cxt->pstore.flags |= PSTORE_FLAGS_FTRACE;
>
> - pr_info("Registered %s as blkzone backend for %s%s%s%s\n",
> + pr_info("Registered %s as blkzone backend for %s%s%s%s%s\n",
> info->name,
> cxt->dbzs && cxt->bzinfo->dump_oops ? "Oops " : "",
> cxt->dbzs && cxt->bzinfo->panic_write ? "Panic " : "",
> cxt->pbz ? "Pmsg " : "",
> - cxt->cbz ? "Console" : "");
> + cxt->cbz ? "Console " : "",
> + cxt->fbzs ? "Ftrace" : "");
>
> err = pstore_register(&cxt->pstore);
> if (err) {
> diff --git a/include/linux/pstore_blk.h b/include/linux/pstore_blk.h
> index 546375e04419..77704c1b404a 100644
> --- a/include/linux/pstore_blk.h
> +++ b/include/linux/pstore_blk.h
> @@ -25,6 +25,9 @@
> * @console_size:
> * The size of zone for console. Zero means disabled, othewise, it must
> * be multiple of SECTOR_SIZE(512).
> + * @ftrace_size:
> + * The size of zone for ftrace. Zero means disabled, othewise, it must
> + * be multiple of SECTOR_SIZE(512).
> * @dump_oops:
> * Dump oops and panic log or only panic.
> * @read, @write:
> @@ -60,6 +63,7 @@ struct blkz_info {
> unsigned long dmesg_size;
> unsigned long pmsg_size;
> unsigned long console_size;
> + unsigned long ftrace_size;
> int dump_oops;
> blkz_read_op read;
> blkz_write_op write;
> --
> 1.9.1
>

--
Kees Cook

Next message: Greg KH: "Re: [PATCH 02/13] coresight: cti: Add sysfs coresight mgmt register access"
Previous message: Kees Cook: "Re: [PATCH v2 04/11] pstore/blk: blkoops: support console recorder"
Next in thread: WeiXiong Liao: "Re: [PATCH v2 05/11] pstore/blk: blkoops: support ftrace recorder"
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