diff mbox series

[PULL,7/9] linux-user: Don't require PROT_READ for mincore

Message ID 20230516124810.90494-8-laurent@vivier.eu (mailing list archive)
State New, archived
Headers show
Series [PULL,1/9] linux-user: Emulate /proc/cpuinfo output for riscv | expand

Commit Message

Laurent Vivier May 16, 2023, 12:48 p.m. UTC 
From: Thomas Weißschuh <thomas@t-8ch.de>

The kernel does not require PROT_READ for addresses passed to mincore.
For example the fincore(1) tool from util-linux uses PROT_NONE and
currently does not work under qemu-user.

Example (with fincore(1) from util-linux 2.38):

$ fincore /proc/self/exe
RES PAGES  SIZE FILE
24K     6 22.1K /proc/self/exe

$ qemu-x86_64 /usr/bin/fincore /proc/self/exe
fincore: failed to do mincore: /proc/self/exe: Cannot allocate memory

With this patch:

$ ./build/qemu-x86_64 /usr/bin/fincore /proc/self/exe
RES PAGES  SIZE FILE
24K     6 22.1K /proc/self/exe

Signed-off-by: Thomas Weißschuh <thomas@t-8ch.de>
Reviewed-by: Laurent Vivier <laurent@vivier.eu>
Message-Id: <20230422100314.1650-3-thomas@t-8ch.de>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>
---
 linux-user/syscall.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
diff mbox series

Patch

diff --git a/linux-user/syscall.c b/linux-user/syscall.c
index 00a779797efb..6655982821ba 100644
--- a/linux-user/syscall.c
+++ b/linux-user/syscall.c
@@ -11993,7 +11993,7 @@  static abi_long do_syscall1(CPUArchState *cpu_env, int num, abi_long arg1,
 #ifdef TARGET_NR_mincore
     case TARGET_NR_mincore:
         {
-            void *a = lock_user(VERIFY_READ, arg1, arg2, 0);
+            void *a = lock_user(VERIFY_NONE, arg1, arg2, 0);
             if (!a) {
                 return -TARGET_ENOMEM;
             }