linux-kernel - [PATCH AUTOSEL 4.9 32/33] parisc: fix warning in flush_tlb

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Message-Id: <20211109010807.1191567-32-sashal@kernel.org>
Date:   Mon,  8 Nov 2021 20:08:06 -0500
From:   Sasha Levin <sashal@...nel.org>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:     Sven Schnelle <svens@...ckframe.org>, Helge Deller <deller@....de>,
        Sasha Levin <sashal@...nel.org>,
        James.Bottomley@...senPartnership.com, dave.hansen@...ux.intel.com,
        wangkefeng.wang@...wei.com, christophe.leroy@....fr,
        akpm@...ux-foundation.org, hanyihao@...o.com, willy@...radead.org,
        linux-parisc@...r.kernel.org
Subject: [PATCH AUTOSEL 4.9 32/33] parisc: fix warning in flush_tlb_all

From: Sven Schnelle <svens@...ckframe.org>

[ Upstream commit 1030d681319b43869e0d5b568b9d0226652d1a6f ]

I've got the following splat after enabling preemption:

[    3.724721] BUG: using __this_cpu_add() in preemptible [00000000] code: swapper/0/1
[    3.734630] caller is __this_cpu_preempt_check+0x38/0x50
[    3.740635] CPU: 1 PID: 1 Comm: swapper/0 Not tainted 5.15.0-rc4-64bit+ #324
[    3.744605] Hardware name: 9000/785/C8000
[    3.744605] Backtrace:
[    3.744605]  [<00000000401d9d58>] show_stack+0x74/0xb0
[    3.744605]  [<0000000040c27bd4>] dump_stack_lvl+0x10c/0x188
[    3.744605]  [<0000000040c27c84>] dump_stack+0x34/0x48
[    3.744605]  [<0000000040c33438>] check_preemption_disabled+0x178/0x1b0
[    3.744605]  [<0000000040c334f8>] __this_cpu_preempt_check+0x38/0x50
[    3.744605]  [<00000000401d632c>] flush_tlb_all+0x58/0x2e0
[    3.744605]  [<00000000401075c0>] 0x401075c0
[    3.744605]  [<000000004010b8fc>] 0x4010b8fc
[    3.744605]  [<00000000401080fc>] 0x401080fc
[    3.744605]  [<00000000401d5224>] do_one_initcall+0x128/0x378
[    3.744605]  [<0000000040102de8>] 0x40102de8
[    3.744605]  [<0000000040c33864>] kernel_init+0x60/0x3a8
[    3.744605]  [<00000000401d1020>] ret_from_kernel_thread+0x20/0x28
[    3.744605]

Fix this by moving the __inc_irq_stat() into the locked section.

Signed-off-by: Sven Schnelle <svens@...ckframe.org>
Signed-off-by: Helge Deller <deller@....de>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 arch/parisc/mm/init.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/parisc/mm/init.c b/arch/parisc/mm/init.c
index dbbe3932f833c..7bdc449615e85 100644
--- a/arch/parisc/mm/init.c
+++ b/arch/parisc/mm/init.c
@@ -940,9 +940,9 @@ void flush_tlb_all(void)
 {
 	int do_recycle;
 
-	__inc_irq_stat(irq_tlb_count);
 	do_recycle = 0;
 	spin_lock(&sid_lock);
+	__inc_irq_stat(irq_tlb_count);
 	if (dirty_space_ids > RECYCLE_THRESHOLD) {
 	    BUG_ON(recycle_inuse);  /* FIXME: Use a semaphore/wait queue here */
 	    get_dirty_sids(&recycle_ndirty,recycle_dirty_array);
@@ -961,8 +961,8 @@ void flush_tlb_all(void)
 #else
 void flush_tlb_all(void)
 {
-	__inc_irq_stat(irq_tlb_count);
 	spin_lock(&sid_lock);
+	__inc_irq_stat(irq_tlb_count);
 	flush_tlb_all_local(NULL);
 	recycle_sids();
 	spin_unlock(&sid_lock);
-- 
2.33.0