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Subject[PATCH] x86/e820: fix e820_search_gap() error handling on x86-32
gcc correctly points out that on 32-bit kernels, e820_search_gap()
not finding a start now leads to pci_mem_start being set to an
uninitialized value:

arch/x86/kernel/e820.c: In function 'e820_setup_gap':
arch/x86/kernel/e820.c:641:16: error: 'gapstart' may be used uninitialized in this function [-Werror=maybe-uninitialized]

This restores the behavior from before the cleanup, defaulting
to address 0x10000000 if nothing was found.

Fixes: b4ed1d15b453 ("x86/e820: Make e820_search_gap() static and remove unused variables")
Signed-off-by: Arnd Bergmann <>
arch/x86/kernel/e820.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kernel/e820.c b/arch/x86/kernel/e820.c
index 46f2afd3577a..b2bbad6ebe4d 100644
--- a/arch/x86/kernel/e820.c
+++ b/arch/x86/kernel/e820.c
@@ -626,14 +626,16 @@ __init void e820_setup_gap(void)
gapsize = 0x400000;
found = e820_search_gap(&gapstart, &gapsize);

-#ifdef CONFIG_X86_64
if (!found) {
+#ifdef CONFIG_X86_64
gapstart = (max_pfn << PAGE_SHIFT) + 1024*1024;
"e820: cannot find a gap in the 32bit address range\n"
"e820: PCI devices with unassigned 32bit BARs may break!\n");
- }
+ gapstart = 0x10000000;
+ }

* e820_reserve_resources_late protect stolen RAM already
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