From ed5d02f0a77849c520e78899ca23c249966f49b9 Mon Sep 17 00:00:00 2001 From: Sumit Garg Date: Fri, 22 Jan 2021 16:35:56 +0530 Subject: [PATCH] kdb: Make memory allocations more robust commit 93f7a6d818deef69d0ba652d46bae6fbabbf365c upstream. Currently kdb uses in_interrupt() to determine whether its library code has been called from the kgdb trap handler or from a saner calling context such as driver init. This approach is broken because in_interrupt() alone isn't able to determine kgdb trap handler entry from normal task context. This can happen during normal use of basic features such as breakpoints and can also be trivially reproduced using: echo g > /proc/sysrq-trigger We can improve this by adding check for in_dbg_master() instead which explicitly determines if we are running in debugger context. Cc: stable@vger.kernel.org Signed-off-by: Sumit Garg Link: https://lore.kernel.org/r/1611313556-4004-1-git-send-email-sumit.garg@linaro.org Signed-off-by: Daniel Thompson Signed-off-by: Greg Kroah-Hartman --- kernel/debug/kdb/kdb_private.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/debug/kdb/kdb_private.h b/kernel/debug/kdb/kdb_private.h index a4281fb99299..81874213b0fe 100644 --- a/kernel/debug/kdb/kdb_private.h +++ b/kernel/debug/kdb/kdb_private.h @@ -230,7 +230,7 @@ extern struct task_struct *kdb_curr_task(int); #define kdb_task_has_cpu(p) (task_curr(p)) -#define GFP_KDB (in_interrupt() ? GFP_ATOMIC : GFP_KERNEL) +#define GFP_KDB (in_dbg_master() ? GFP_ATOMIC : GFP_KERNEL) extern void *debug_kmalloc(size_t size, gfp_t flags); extern void debug_kfree(void *);