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authorRichard Weinberger <richard@nod.at>2015-08-09 22:26:33 +0200
committerRichard Weinberger <richard@nod.at>2015-10-19 22:53:37 +0200
commit56b88a3bf97a39d3f4f010509917b76a865a6dc8 (patch)
tree408b519405bd8545f8da4102ac120db58d2a1f3e
parent6b1873371cea13036171d03a7c1e3e59158b4505 (diff)
um: Fix kernel mode fault condition
We have to exclude memory locations <= PAGE_SIZE from the condition and let the kernel mode fault path catch it. Otherwise a kernel NULL pointer exception will be reported as a kernel user space access. Fixes: d2313084e2c (um: Catch unprotected user memory access) Signed-off-by: Richard Weinberger <richard@nod.at>
-rw-r--r--arch/um/kernel/trap.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/um/kernel/trap.c b/arch/um/kernel/trap.c
index d8a9fce6ee2e..98783dd0fa2e 100644
--- a/arch/um/kernel/trap.c
+++ b/arch/um/kernel/trap.c
@@ -220,7 +220,7 @@ unsigned long segv(struct faultinfo fi, unsigned long ip, int is_user,
show_regs(container_of(regs, struct pt_regs, regs));
panic("Segfault with no mm");
}
- else if (!is_user && address < TASK_SIZE) {
+ else if (!is_user && address > PAGE_SIZE && address < TASK_SIZE) {
show_regs(container_of(regs, struct pt_regs, regs));
panic("Kernel tried to access user memory at addr 0x%lx, ip 0x%lx",
address, ip);