Dear stable kernel team,
could you please add the patch below to all stable kernels
from v4.19 up to 5.15.
It's a manual backport of upstream commit 61e150fb310729c98227a5edf6e4a3619edc3702,
which doesn't applies cleanly otherwise.
Thanks!
Helge
>From 97d6d8f6248364ec916e9642a58f1ed14a1eb147 Mon Sep 17 00:00:00 2001
From: Helge Deller <deller@xxxxxx>
Date: Fri, 26 May 2023 22:51:07 +0200
Subject: [PATCH] parisc: Fix flush_dcache_page() for usage from irq context
flush_dcache_page() may be called with IRQs disabled.
But the current implementation for flush_dcache_page() on parisc
unintentionally re-enables IRQs, which may lead to deadlocks.
Fix it by using xa_lock_irqsave() and xa_unlock_irqrestore()
for the flush_dcache_mmap_*lock() macros instead.
Signed-off-by: Helge Deller <deller@xxxxxx>
---
arch/parisc/include/asm/cacheflush.h | 5 +++++
arch/parisc/kernel/cache.c | 5 +++--
2 files changed, 8 insertions(+), 2 deletions(-)
diff --git a/arch/parisc/include/asm/cacheflush.h b/arch/parisc/include/asm/cacheflush.h
index eef0096db5f8..2f4c45f60ae1 100644
--- a/arch/parisc/include/asm/cacheflush.h
+++ b/arch/parisc/include/asm/cacheflush.h
@@ -53,6 +53,11 @@ extern void flush_dcache_page(struct page *page);
#define flush_dcache_mmap_lock(mapping) xa_lock_irq(&mapping->i_pages)
#define flush_dcache_mmap_unlock(mapping) xa_unlock_irq(&mapping->i_pages)
+#define flush_dcache_mmap_lock_irqsave(mapping, flags) \
+ xa_lock_irqsave(&mapping->i_pages, flags)
+#define flush_dcache_mmap_unlock_irqrestore(mapping, flags) \
+ xa_unlock_irqrestore(&mapping->i_pages, flags)
+
#define flush_icache_page(vma,page) do { \
flush_kernel_dcache_page_addr(page_address(page)); \
diff --git a/arch/parisc/kernel/cache.c b/arch/parisc/kernel/cache.c
index 394e6e14e5c4..c473c2f395a0 100644
--- a/arch/parisc/kernel/cache.c
+++ b/arch/parisc/kernel/cache.c
@@ -324,6 +324,7 @@ void flush_dcache_page(struct page *page)
struct vm_area_struct *mpnt;
unsigned long offset;
unsigned long addr, old_addr = 0;
+ unsigned long flags;
pgoff_t pgoff;
if (mapping && !mapping_mapped(mapping)) {
@@ -343,7 +344,7 @@ void flush_dcache_page(struct page *page)
* declared as MAP_PRIVATE or MAP_SHARED), so we only need
* to flush one address here for them all to become coherent */
- flush_dcache_mmap_lock(mapping);
+ flush_dcache_mmap_lock_irqsave(mapping, flags);
vma_interval_tree_foreach(mpnt, &mapping->i_mmap, pgoff, pgoff) {
offset = (pgoff - mpnt->vm_pgoff) << PAGE_SHIFT;
addr = mpnt->vm_start + offset;
@@ -366,7 +367,7 @@ void flush_dcache_page(struct page *page)
old_addr = addr;
}
}
- flush_dcache_mmap_unlock(mapping);
+ flush_dcache_mmap_unlock_irqrestore(mapping, flags);
}
EXPORT_SYMBOL(flush_dcache_page);
--
2.38.1
