From patchwork Fri Aug 2 04:22:33 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Christopher M. Riedl" X-Patchwork-Id: 1140969 Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from lists.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 460Dc62Sp9z9s7T for ; Fri, 2 Aug 2019 14:25:42 +1000 (AEST) Authentication-Results: ozlabs.org; dmarc=none (p=none dis=none) header.from=informatik.wtf Received: from lists.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 460Dc60wynzDqwh for ; Fri, 2 Aug 2019 14:25:42 +1000 (AEST) X-Original-To: linuxppc-dev@lists.ozlabs.org Delivered-To: linuxppc-dev@lists.ozlabs.org Received: from ozlabs.org (bilbo.ozlabs.org [203.11.71.1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 460DT26NxNzDqkV for ; Fri, 2 Aug 2019 14:19:34 +1000 (AEST) Authentication-Results: lists.ozlabs.org; dmarc=none (p=none dis=none) header.from=informatik.wtf Received: from ozlabs.org (bilbo.ozlabs.org [IPv6:2401:3900:2:1::2]) by bilbo.ozlabs.org (Postfix) with ESMTP id 460DT25qXpz8t7p for ; Fri, 2 Aug 2019 14:19:34 +1000 (AEST) Received: by ozlabs.org (Postfix) id 460DT25bGFz9sBF; Fri, 2 Aug 2019 14:19:34 +1000 (AEST) Delivered-To: linuxppc-dev@ozlabs.org Authentication-Results: ozlabs.org; spf=pass (mailfrom) smtp.mailfrom=informatik.wtf (client-ip=131.153.2.43; helo=h2.fbrelay.privateemail.com; envelope-from=cmr@informatik.wtf; receiver=) Authentication-Results: ozlabs.org; dmarc=none (p=none dis=none) header.from=informatik.wtf Received: from h2.fbrelay.privateemail.com (h2.fbrelay.privateemail.com [131.153.2.43]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 460DT21BMvz9s3Z for ; Fri, 2 Aug 2019 14:19:34 +1000 (AEST) Received: from MTA-06-3.privateemail.com (mta-06.privateemail.com [68.65.122.16]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by h1.fbrelay.privateemail.com (Postfix) with ESMTPS id DA2D9814DC for ; Fri, 2 Aug 2019 00:19:31 -0400 (EDT) Received: from MTA-06.privateemail.com (localhost [127.0.0.1]) by MTA-06.privateemail.com (Postfix) with ESMTP id 8A46860045; Fri, 2 Aug 2019 00:19:28 -0400 (EDT) Received: from wrwlf0000.attlocal.net (unknown [10.20.151.234]) by MTA-06.privateemail.com (Postfix) with ESMTPA id 236B160039; Fri, 2 Aug 2019 04:19:28 +0000 (UTC) From: "Christopher M. Riedl" To: linuxppc-dev@ozlabs.org Subject: [PATCH v2 3/3] powerpc/spinlocks: Fix oops in shared-processor spinlocks Date: Thu, 1 Aug 2019 23:22:33 -0500 Message-Id: <20190802042233.20835-4-cmr@informatik.wtf> X-Mailer: git-send-email 2.22.0 In-Reply-To: <20190802042233.20835-1-cmr@informatik.wtf> References: <20190802042233.20835-1-cmr@informatik.wtf> MIME-Version: 1.0 X-Virus-Scanned: ClamAV using ClamSMTP X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: "Christopher M. Riedl" , ajd@linux.ibm.com, bauerman@linux.ibm.com Errors-To: linuxppc-dev-bounces+patchwork-incoming=ozlabs.org@lists.ozlabs.org Sender: "Linuxppc-dev" Booting w/ ppc64le_defconfig + CONFIG_PREEMPT results in the attached kernel trace due to calling shared-processor spinlocks while not running in an SPLPAR. Previously, the out-of-line spinlocks implementations were selected based on CONFIG_PPC_SPLPAR at compile time without a runtime shared-processor LPAR check. To fix, call the actual spinlock implementations from a set of common functions, spin_yield() and rw_yield(), which check for shared-processor LPAR during runtime and select the appropriate lock implementation. [ 0.430878] BUG: Kernel NULL pointer dereference at 0x00000100 [ 0.431991] Faulting instruction address: 0xc000000000097f88 [ 0.432934] Oops: Kernel access of bad area, sig: 7 [#1] [ 0.433448] LE PAGE_SIZE=64K MMU=Radix MMU=Hash PREEMPT SMP NR_CPUS=2048 NUMA PowerNV [ 0.434479] Modules linked in: [ 0.435055] CPU: 0 PID: 2 Comm: kthreadd Not tainted 5.2.0-rc6-00491-g249155c20f9b #28 [ 0.435730] NIP: c000000000097f88 LR: c000000000c07a88 CTR: c00000000015ca10 [ 0.436383] REGS: c0000000727079f0 TRAP: 0300 Not tainted (5.2.0-rc6-00491-g249155c20f9b) [ 0.437004] MSR: 9000000002009033 CR: 84000424 XER: 20040000 [ 0.437874] CFAR: c000000000c07a84 DAR: 0000000000000100 DSISR: 00080000 IRQMASK: 1 [ 0.437874] GPR00: c000000000c07a88 c000000072707c80 c000000001546300 c00000007be38a80 [ 0.437874] GPR04: c0000000726f0c00 0000000000000002 c00000007279c980 0000000000000100 [ 0.437874] GPR08: c000000001581b78 0000000080000001 0000000000000008 c00000007279c9b0 [ 0.437874] GPR12: 0000000000000000 c000000001730000 c000000000142558 0000000000000000 [ 0.437874] GPR16: 0000000000000000 0000000000000000 0000000000000000 0000000000000000 [ 0.437874] GPR20: 0000000000000000 0000000000000000 0000000000000000 0000000000000000 [ 0.437874] GPR24: c00000007be38a80 c000000000c002f4 0000000000000000 0000000000000000 [ 0.437874] GPR28: c000000072221a00 c0000000726c2600 c00000007be38a80 c00000007be38a80 [ 0.443992] NIP [c000000000097f88] __spin_yield+0x48/0xa0 [ 0.444523] LR [c000000000c07a88] __raw_spin_lock+0xb8/0xc0 [ 0.445080] Call Trace: [ 0.445670] [c000000072707c80] [c000000072221a00] 0xc000000072221a00 (unreliable) [ 0.446425] [c000000072707cb0] [c000000000bffb0c] __schedule+0xbc/0x850 [ 0.447078] [c000000072707d70] [c000000000c002f4] schedule+0x54/0x130 [ 0.447694] [c000000072707da0] [c0000000001427dc] kthreadd+0x28c/0x2b0 [ 0.448389] [c000000072707e20] [c00000000000c1cc] ret_from_kernel_thread+0x5c/0x70 [ 0.449143] Instruction dump: [ 0.449821] 4d9e0020 552a043e 210a07ff 79080fe0 0b080000 3d020004 3908b878 794a1f24 [ 0.450587] e8e80000 7ce7502a e8e70000 38e70100 <7ca03c2c> 70a70001 78a50020 4d820020 [ 0.452808] ---[ end trace 474d6b2b8fc5cb7e ]--- Signed-off-by: Christopher M. Riedl --- arch/powerpc/include/asm/spinlock.h | 36 ++++++++++++++++++++--------- 1 file changed, 25 insertions(+), 11 deletions(-) diff --git a/arch/powerpc/include/asm/spinlock.h b/arch/powerpc/include/asm/spinlock.h index 0a8270183770..6aed8a83b180 100644 --- a/arch/powerpc/include/asm/spinlock.h +++ b/arch/powerpc/include/asm/spinlock.h @@ -103,11 +103,9 @@ static inline int arch_spin_trylock(arch_spinlock_t *lock) /* We only yield to the hypervisor if we are in shared processor mode */ void splpar_spin_yield(arch_spinlock_t *lock); void splpar_rw_yield(arch_rwlock_t *lock); -#define __spin_yield(x) splpar_spin_yield(x) -#define __rw_yield(x) splpar_rw_yield(x) #else /* SPLPAR */ -#define __spin_yield(x) barrier() -#define __rw_yield(x) barrier() +static inline void splpar_spin_yield(arch_spinlock_t *lock) {}; +static inline void splpar_rw_yield(arch_rwlock_t *lock) {}; #endif static inline bool is_shared_processor(void) @@ -124,6 +122,22 @@ static inline bool is_shared_processor(void) #endif } +static inline void spin_yield(arch_spinlock_t *lock) +{ + if (is_shared_processor()) + splpar_spin_yield(lock); + else + barrier(); +} + +static inline void rw_yield(arch_rwlock_t *lock) +{ + if (is_shared_processor()) + splpar_rw_yield(lock); + else + barrier(); +} + static inline void arch_spin_lock(arch_spinlock_t *lock) { while (1) { @@ -132,7 +146,7 @@ static inline void arch_spin_lock(arch_spinlock_t *lock) do { HMT_low(); if (is_shared_processor()) - __spin_yield(lock); + spin_yield(lock); } while (unlikely(lock->slock != 0)); HMT_medium(); } @@ -151,7 +165,7 @@ void arch_spin_lock_flags(arch_spinlock_t *lock, unsigned long flags) do { HMT_low(); if (is_shared_processor()) - __spin_yield(lock); + spin_yield(lock); } while (unlikely(lock->slock != 0)); HMT_medium(); local_irq_restore(flags_dis); @@ -241,7 +255,7 @@ static inline void arch_read_lock(arch_rwlock_t *rw) do { HMT_low(); if (is_shared_processor()) - __rw_yield(rw); + rw_yield(rw); } while (unlikely(rw->lock < 0)); HMT_medium(); } @@ -255,7 +269,7 @@ static inline void arch_write_lock(arch_rwlock_t *rw) do { HMT_low(); if (is_shared_processor()) - __rw_yield(rw); + rw_yield(rw); } while (unlikely(rw->lock != 0)); HMT_medium(); } @@ -295,9 +309,9 @@ static inline void arch_write_unlock(arch_rwlock_t *rw) rw->lock = 0; } -#define arch_spin_relax(lock) __spin_yield(lock) -#define arch_read_relax(lock) __rw_yield(lock) -#define arch_write_relax(lock) __rw_yield(lock) +#define arch_spin_relax(lock) spin_yield(lock) +#define arch_read_relax(lock) rw_yield(lock) +#define arch_write_relax(lock) rw_yield(lock) /* See include/linux/spinlock.h */ #define smp_mb__after_spinlock() smp_mb()