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Subject[PATCH] x86/mm/mem_encrypt: fix a crash with kmemleak_scan
Date
The first kmemleak_scan() after boot would trigger a crash below because

kernel_init
free_initmem
mem_encrypt_free_decrypted_mem
free_init_pages

unmapped some memory inside the .bss.

BUG: unable to handle kernel paging request at ffffffffbd402000
CPU: 12 PID: 325 Comm: kmemleak Not tainted 5.1.0-rc4+ #4
RIP: 0010:scan_block+0x58/0x160
Call Trace:
scan_gray_list+0x1d9/0x280
kmemleak_scan+0x485/0xad0
kmemleak_scan_thread+0x9f/0xc4
kthread+0x1d2/0x1f0
ret_from_fork+0x35/0x40

Signed-off-by: Qian Cai <cai@lca.pw>
---
arch/x86/mm/mem_encrypt.c | 6 ++++++
1 file changed, 6 insertions(+)

diff --git a/arch/x86/mm/mem_encrypt.c b/arch/x86/mm/mem_encrypt.c
index 385afa2b9e17..614ab156024f 100644
--- a/arch/x86/mm/mem_encrypt.c
+++ b/arch/x86/mm/mem_encrypt.c
@@ -18,6 +18,7 @@
#include <linux/dma-direct.h>
#include <linux/swiotlb.h>
#include <linux/mem_encrypt.h>
+#include <linux/kmemleak.h>

#include <asm/tlbflush.h>
#include <asm/fixmap.h>
@@ -369,6 +370,11 @@ void __init mem_encrypt_free_decrypted_mem(void)
}
}

+ /*
+ * Inform kmemleak about the hole in the .bss section since the
+ * corresponding pages will be unmapped with DEBUG_PAGEALLOC=y.
+ */
+ kmemleak_free_part((void *)vaddr, vaddr_end - vaddr);
free_init_pages("unused decrypted", vaddr, vaddr_end);
}

--
2.17.2 (Apple Git-113)
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