Revision 787252a10d9422f3058df9a4821f389e5326c440 authored by Nathan Lynch on 15 October 2021, 17:39:02 UTC, committed by Michael Ellerman on 20 October 2021, 10:38:01 UTC
With PREEMPT_COUNT=y, when a CPU is offlined and then onlined again, we get: BUG: scheduling while atomic: swapper/1/0/0x00000000 no locks held by swapper/1/0. CPU: 1 PID: 0 Comm: swapper/1 Not tainted 5.15.0-rc2+ #100 Call Trace: dump_stack_lvl+0xac/0x108 __schedule_bug+0xac/0xe0 __schedule+0xcf8/0x10d0 schedule_idle+0x3c/0x70 do_idle+0x2d8/0x4a0 cpu_startup_entry+0x38/0x40 start_secondary+0x2ec/0x3a0 start_secondary_prolog+0x10/0x14 This is because powerpc's arch_cpu_idle_dead() decrements the idle task's preempt count, for reasons explained in commit a7c2bb8279d2 ("powerpc: Re-enable preemption before cpu_die()"), specifically "start_secondary() expects a preempt_count() of 0." However, since commit 2c669ef6979c ("powerpc/preempt: Don't touch the idle task's preempt_count during hotplug") and commit f1a0a376ca0c ("sched/core: Initialize the idle task with preemption disabled"), that justification no longer holds. The idle task isn't supposed to re-enable preemption, so remove the vestigial preempt_enable() from the CPU offline path. Tested with pseries and powernv in qemu, and pseries on PowerVM. Fixes: 2c669ef6979c ("powerpc/preempt: Don't touch the idle task's preempt_count during hotplug") Signed-off-by: Nathan Lynch <nathanl@linux.ibm.com> Reviewed-by: Valentin Schneider <valentin.schneider@arm.com> Reviewed-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20211015173902.2278118-1-nathanl@linux.ibm.com
1 parent 496c5fe
zstd.c
// SPDX-License-Identifier: GPL-2.0-only
/*
* Cryptographic API.
*
* Copyright (c) 2017-present, Facebook, Inc.
*/
#include <linux/crypto.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/mm.h>
#include <linux/module.h>
#include <linux/net.h>
#include <linux/vmalloc.h>
#include <linux/zstd.h>
#include <crypto/internal/scompress.h>
#define ZSTD_DEF_LEVEL 3
struct zstd_ctx {
ZSTD_CCtx *cctx;
ZSTD_DCtx *dctx;
void *cwksp;
void *dwksp;
};
static ZSTD_parameters zstd_params(void)
{
return ZSTD_getParams(ZSTD_DEF_LEVEL, 0, 0);
}
static int zstd_comp_init(struct zstd_ctx *ctx)
{
int ret = 0;
const ZSTD_parameters params = zstd_params();
const size_t wksp_size = ZSTD_CCtxWorkspaceBound(params.cParams);
ctx->cwksp = vzalloc(wksp_size);
if (!ctx->cwksp) {
ret = -ENOMEM;
goto out;
}
ctx->cctx = ZSTD_initCCtx(ctx->cwksp, wksp_size);
if (!ctx->cctx) {
ret = -EINVAL;
goto out_free;
}
out:
return ret;
out_free:
vfree(ctx->cwksp);
goto out;
}
static int zstd_decomp_init(struct zstd_ctx *ctx)
{
int ret = 0;
const size_t wksp_size = ZSTD_DCtxWorkspaceBound();
ctx->dwksp = vzalloc(wksp_size);
if (!ctx->dwksp) {
ret = -ENOMEM;
goto out;
}
ctx->dctx = ZSTD_initDCtx(ctx->dwksp, wksp_size);
if (!ctx->dctx) {
ret = -EINVAL;
goto out_free;
}
out:
return ret;
out_free:
vfree(ctx->dwksp);
goto out;
}
static void zstd_comp_exit(struct zstd_ctx *ctx)
{
vfree(ctx->cwksp);
ctx->cwksp = NULL;
ctx->cctx = NULL;
}
static void zstd_decomp_exit(struct zstd_ctx *ctx)
{
vfree(ctx->dwksp);
ctx->dwksp = NULL;
ctx->dctx = NULL;
}
static int __zstd_init(void *ctx)
{
int ret;
ret = zstd_comp_init(ctx);
if (ret)
return ret;
ret = zstd_decomp_init(ctx);
if (ret)
zstd_comp_exit(ctx);
return ret;
}
static void *zstd_alloc_ctx(struct crypto_scomp *tfm)
{
int ret;
struct zstd_ctx *ctx;
ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);
if (!ctx)
return ERR_PTR(-ENOMEM);
ret = __zstd_init(ctx);
if (ret) {
kfree(ctx);
return ERR_PTR(ret);
}
return ctx;
}
static int zstd_init(struct crypto_tfm *tfm)
{
struct zstd_ctx *ctx = crypto_tfm_ctx(tfm);
return __zstd_init(ctx);
}
static void __zstd_exit(void *ctx)
{
zstd_comp_exit(ctx);
zstd_decomp_exit(ctx);
}
static void zstd_free_ctx(struct crypto_scomp *tfm, void *ctx)
{
__zstd_exit(ctx);
kfree_sensitive(ctx);
}
static void zstd_exit(struct crypto_tfm *tfm)
{
struct zstd_ctx *ctx = crypto_tfm_ctx(tfm);
__zstd_exit(ctx);
}
static int __zstd_compress(const u8 *src, unsigned int slen,
u8 *dst, unsigned int *dlen, void *ctx)
{
size_t out_len;
struct zstd_ctx *zctx = ctx;
const ZSTD_parameters params = zstd_params();
out_len = ZSTD_compressCCtx(zctx->cctx, dst, *dlen, src, slen, params);
if (ZSTD_isError(out_len))
return -EINVAL;
*dlen = out_len;
return 0;
}
static int zstd_compress(struct crypto_tfm *tfm, const u8 *src,
unsigned int slen, u8 *dst, unsigned int *dlen)
{
struct zstd_ctx *ctx = crypto_tfm_ctx(tfm);
return __zstd_compress(src, slen, dst, dlen, ctx);
}
static int zstd_scompress(struct crypto_scomp *tfm, const u8 *src,
unsigned int slen, u8 *dst, unsigned int *dlen,
void *ctx)
{
return __zstd_compress(src, slen, dst, dlen, ctx);
}
static int __zstd_decompress(const u8 *src, unsigned int slen,
u8 *dst, unsigned int *dlen, void *ctx)
{
size_t out_len;
struct zstd_ctx *zctx = ctx;
out_len = ZSTD_decompressDCtx(zctx->dctx, dst, *dlen, src, slen);
if (ZSTD_isError(out_len))
return -EINVAL;
*dlen = out_len;
return 0;
}
static int zstd_decompress(struct crypto_tfm *tfm, const u8 *src,
unsigned int slen, u8 *dst, unsigned int *dlen)
{
struct zstd_ctx *ctx = crypto_tfm_ctx(tfm);
return __zstd_decompress(src, slen, dst, dlen, ctx);
}
static int zstd_sdecompress(struct crypto_scomp *tfm, const u8 *src,
unsigned int slen, u8 *dst, unsigned int *dlen,
void *ctx)
{
return __zstd_decompress(src, slen, dst, dlen, ctx);
}
static struct crypto_alg alg = {
.cra_name = "zstd",
.cra_driver_name = "zstd-generic",
.cra_flags = CRYPTO_ALG_TYPE_COMPRESS,
.cra_ctxsize = sizeof(struct zstd_ctx),
.cra_module = THIS_MODULE,
.cra_init = zstd_init,
.cra_exit = zstd_exit,
.cra_u = { .compress = {
.coa_compress = zstd_compress,
.coa_decompress = zstd_decompress } }
};
static struct scomp_alg scomp = {
.alloc_ctx = zstd_alloc_ctx,
.free_ctx = zstd_free_ctx,
.compress = zstd_scompress,
.decompress = zstd_sdecompress,
.base = {
.cra_name = "zstd",
.cra_driver_name = "zstd-scomp",
.cra_module = THIS_MODULE,
}
};
static int __init zstd_mod_init(void)
{
int ret;
ret = crypto_register_alg(&alg);
if (ret)
return ret;
ret = crypto_register_scomp(&scomp);
if (ret)
crypto_unregister_alg(&alg);
return ret;
}
static void __exit zstd_mod_fini(void)
{
crypto_unregister_alg(&alg);
crypto_unregister_scomp(&scomp);
}
subsys_initcall(zstd_mod_init);
module_exit(zstd_mod_fini);
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("Zstd Compression Algorithm");
MODULE_ALIAS_CRYPTO("zstd");
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