From: Sumit Garg Date: Fri, 22 Jan 2021 11:05:56 +0000 (+0530) Subject: kdb: Make memory allocations more robust X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=93f7a6d818deef69d0ba652d46bae6fbabbf365c;p=linux.git kdb: Make memory allocations more robust 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 --- diff --git a/kernel/debug/kdb/kdb_private.h b/kernel/debug/kdb/kdb_private.h index 0a56d35f6eea2..6cb92f7bbbd0c 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 *);