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
| File | Mode | Size |
|---|---|---|
| asymmetric_keys | ||
| async_tx | ||
| 842.c | -rw-r--r-- | 3.7 KB |
| Kconfig | -rw-r--r-- | 55.6 KB |
| Makefile | -rw-r--r-- | 7.6 KB |
| acompress.c | -rw-r--r-- | 4.7 KB |
| adiantum.c | -rw-r--r-- | 19.5 KB |
| aead.c | -rw-r--r-- | 7.2 KB |
| aegis.h | -rw-r--r-- | 2.5 KB |
| aegis128-core.c | -rw-r--r-- | 15.6 KB |
| aegis128-neon-inner.c | -rw-r--r-- | 8.4 KB |
| aegis128-neon.c | -rw-r--r-- | 2.0 KB |
| aes_generic.c | -rw-r--r-- | 57.6 KB |
| aes_ti.c | -rw-r--r-- | 2.0 KB |
| af_alg.c | -rw-r--r-- | 26.8 KB |
| ahash.c | -rw-r--r-- | 15.7 KB |
| akcipher.c | -rw-r--r-- | 4.0 KB |
| algapi.c | -rw-r--r-- | 29.2 KB |
| algboss.c | -rw-r--r-- | 5.4 KB |
| algif_aead.c | -rw-r--r-- | 15.6 KB |
| algif_hash.c | -rw-r--r-- | 9.5 KB |
| algif_rng.c | -rw-r--r-- | 8.4 KB |
| algif_skcipher.c | -rw-r--r-- | 9.6 KB |
| ansi_cprng.c | -rw-r--r-- | 10.8 KB |
| anubis.c | -rw-r--r-- | 27.8 KB |
| api.c | -rw-r--r-- | 13.8 KB |
| arc4.c | -rw-r--r-- | 2.1 KB |
| authenc.c | -rw-r--r-- | 13.1 KB |
| authencesn.c | -rw-r--r-- | 14.2 KB |
| blake2b_generic.c | -rw-r--r-- | 5.9 KB |
| blake2s_generic.c | -rw-r--r-- | 2.3 KB |
| blowfish_common.c | -rw-r--r-- | 15.5 KB |
| blowfish_generic.c | -rw-r--r-- | 3.1 KB |
| camellia_generic.c | -rw-r--r-- | 34.0 KB |
| cast5_generic.c | -rw-r--r-- | 20.4 KB |
| cast6_generic.c | -rw-r--r-- | 9.1 KB |
| cast_common.c | -rw-r--r-- | 12.9 KB |
| cbc.c | -rw-r--r-- | 5.2 KB |
| ccm.c | -rw-r--r-- | 23.5 KB |
| cfb.c | -rw-r--r-- | 6.2 KB |
| chacha20poly1305.c | -rw-r--r-- | 17.7 KB |
| chacha_generic.c | -rw-r--r-- | 3.9 KB |
| cipher.c | -rw-r--r-- | 2.6 KB |
| cmac.c | -rw-r--r-- | 7.6 KB |
| compress.c | -rw-r--r-- | 921 bytes |
| crc32_generic.c | -rw-r--r-- | 2.8 KB |
| crc32c_generic.c | -rw-r--r-- | 4.1 KB |
| crct10dif_common.c | -rw-r--r-- | 3.6 KB |
| crct10dif_generic.c | -rw-r--r-- | 3.1 KB |
| cryptd.c | -rw-r--r-- | 28.6 KB |
| crypto_engine.c | -rw-r--r-- | 15.3 KB |
| crypto_null.c | -rw-r--r-- | 5.3 KB |
| crypto_user_base.c | -rw-r--r-- | 12.0 KB |
| crypto_user_stat.c | -rw-r--r-- | 9.6 KB |
| ctr.c | -rw-r--r-- | 9.6 KB |
| cts.c | -rw-r--r-- | 11.5 KB |
| curve25519-generic.c | -rw-r--r-- | 2.2 KB |
| deflate.c | -rw-r--r-- | 7.7 KB |
| des_generic.c | -rw-r--r-- | 3.3 KB |
| dh.c | -rw-r--r-- | 5.4 KB |
| dh_helper.c | -rw-r--r-- | 3.4 KB |
| drbg.c | -rw-r--r-- | 59.8 KB |
| ecb.c | -rw-r--r-- | 2.4 KB |
| ecc.c | -rw-r--r-- | 42.0 KB |
| ecc.h | -rw-r--r-- | 7.8 KB |
| ecc_curve_defs.h | -rw-r--r-- | 3.7 KB |
| ecdh.c | -rw-r--r-- | 5.7 KB |
| ecdh_helper.c | -rw-r--r-- | 2.0 KB |
| ecdsa.c | -rw-r--r-- | 9.2 KB |
| ecdsasignature.asn1 | -rw-r--r-- | 111 bytes |
| echainiv.c | -rw-r--r-- | 4.1 KB |
| ecrdsa.c | -rw-r--r-- | 8.4 KB |
| ecrdsa_defs.h | -rw-r--r-- | 7.2 KB |
| ecrdsa_params.asn1 | -rw-r--r-- | 142 bytes |
| ecrdsa_pub_key.asn1 | -rw-r--r-- | 57 bytes |
| essiv.c | -rw-r--r-- | 17.9 KB |
| fcrypt.c | -rw-r--r-- | 18.0 KB |
| fips.c | -rw-r--r-- | 1.7 KB |
| gcm.c | -rw-r--r-- | 30.0 KB |
| geniv.c | -rw-r--r-- | 3.8 KB |
| gf128mul.c | -rw-r--r-- | 12.5 KB |
| ghash-generic.c | -rw-r--r-- | 4.8 KB |
| hash_info.c | -rw-r--r-- | 1.9 KB |
| hmac.c | -rw-r--r-- | 6.4 KB |
| internal.h | -rw-r--r-- | 4.0 KB |
| jitterentropy-kcapi.c | -rw-r--r-- | 6.2 KB |
| jitterentropy.c | -rw-r--r-- | 25.2 KB |
| jitterentropy.h | -rw-r--r-- | 643 bytes |
| keywrap.c | -rw-r--r-- | 9.5 KB |
| khazad.c | -rw-r--r-- | 51.8 KB |
| kpp.c | -rw-r--r-- | 2.7 KB |
| lrw.c | -rw-r--r-- | 10.6 KB |
| lz4.c | -rw-r--r-- | 3.3 KB |
| lz4hc.c | -rw-r--r-- | 3.4 KB |
| lzo-rle.c | -rw-r--r-- | 3.4 KB |
| lzo.c | -rw-r--r-- | 3.3 KB |
| md4.c | -rw-r--r-- | 5.9 KB |
| md5.c | -rw-r--r-- | 7.4 KB |
| memneq.c | -rw-r--r-- | 6.1 KB |
| michael_mic.c | -rw-r--r-- | 3.4 KB |
| nhpoly1305.c | -rw-r--r-- | 7.8 KB |
| ofb.c | -rw-r--r-- | 2.5 KB |
| pcbc.c | -rw-r--r-- | 4.7 KB |
| pcrypt.c | -rw-r--r-- | 9.2 KB |
| poly1305_generic.c | -rw-r--r-- | 3.7 KB |
| proc.c | -rw-r--r-- | 2.5 KB |
| ripemd.h | -rw-r--r-- | 655 bytes |
| rmd160.c | -rw-r--r-- | 12.4 KB |
| rng.c | -rw-r--r-- | 4.7 KB |
| rsa-pkcs1pad.c | -rw-r--r-- | 17.3 KB |
| rsa.c | -rw-r--r-- | 5.3 KB |
| rsa_helper.c | -rw-r--r-- | 4.0 KB |
| rsaprivkey.asn1 | -rw-r--r-- | 316 bytes |
| rsapubkey.asn1 | -rw-r--r-- | 82 bytes |
| scatterwalk.c | -rw-r--r-- | 2.0 KB |
| scompress.c | -rw-r--r-- | 6.8 KB |
| seed.c | -rw-r--r-- | 17.2 KB |
| seqiv.c | -rw-r--r-- | 4.5 KB |
| serpent_generic.c | -rw-r--r-- | 19.6 KB |
| sha1_generic.c | -rw-r--r-- | 2.3 KB |
| sha256_generic.c | -rw-r--r-- | 3.3 KB |
| sha3_generic.c | -rw-r--r-- | 8.0 KB |
| sha512_generic.c | -rw-r--r-- | 7.7 KB |
| shash.c | -rw-r--r-- | 15.5 KB |
| simd.c | -rw-r--r-- | 13.5 KB |
| skcipher.c | -rw-r--r-- | 24.7 KB |
| sm2.c | -rw-r--r-- | 9.8 KB |
| sm2signature.asn1 | -rw-r--r-- | 113 bytes |
| sm3_generic.c | -rw-r--r-- | 4.1 KB |
| sm4_generic.c | -rw-r--r-- | 2.1 KB |
| streebog_generic.c | -rw-r--r-- | 57.6 KB |
| tcrypt.c | -rw-r--r-- | 79.5 KB |
| tcrypt.h | -rw-r--r-- | 3.0 KB |
| tea.c | -rw-r--r-- | 6.5 KB |
| testmgr.c | -rw-r--r-- | 145.4 KB |
| testmgr.h | -rw-r--r-- | 1.2 MB |
| twofish_common.c | -rw-r--r-- | 37.1 KB |
| twofish_generic.c | -rw-r--r-- | 5.5 KB |
| vmac.c | -rw-r--r-- | 18.9 KB |
| wp512.c | -rw-r--r-- | 59.7 KB |
| xcbc.c | -rw-r--r-- | 6.7 KB |
| xor.c | -rw-r--r-- | 3.8 KB |
| xts.c | -rw-r--r-- | 11.8 KB |
| xxhash_generic.c | -rw-r--r-- | 2.4 KB |
| zstd.c | -rw-r--r-- | 5.0 KB |
Computing file changes ...
