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authorDouglas Anderson <dianders@chromium.org>2019-07-25 11:35:51 -0700
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2019-07-30 17:39:39 +0200
commit81eaadcae81b4c1bf01649a3053d1f54e2d81cf1 (patch)
treeb56e875a012663ed62600fe70f3f5b34cc1b5475 /drivers
parent609488bc979f99f805f34e9a32c1e3b71179d10b (diff)
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kgdboc: disable the console lock when in kgdb
After commit ddde3c18b700 ("vt: More locking checks") kdb / kgdb has become useless because my console is filled with spews of: WARNING: CPU: 0 PID: 0 at .../drivers/tty/vt/vt.c:3846 con_is_visible+0x50/0x74 CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.3.0-rc1+ #48 Hardware name: Rockchip (Device Tree) Backtrace: [<c020ce9c>] (dump_backtrace) from [<c020d188>] (show_stack+0x20/0x24) [<c020d168>] (show_stack) from [<c0a8fc14>] (dump_stack+0xb0/0xd0) [<c0a8fb64>] (dump_stack) from [<c0232c58>] (__warn+0xec/0x11c) [<c0232b6c>] (__warn) from [<c0232dc4>] (warn_slowpath_null+0x4c/0x58) [<c0232d78>] (warn_slowpath_null) from [<c06338a0>] (con_is_visible+0x50/0x74) [<c0633850>] (con_is_visible) from [<c0634078>] (con_scroll+0x108/0x1ac) [<c0633f70>] (con_scroll) from [<c0634160>] (lf+0x44/0x88) [<c063411c>] (lf) from [<c06363ec>] (vt_console_print+0x1a4/0x2bc) [<c0636248>] (vt_console_print) from [<c02f628c>] (vkdb_printf+0x420/0x8a4) [<c02f5e6c>] (vkdb_printf) from [<c02f6754>] (kdb_printf+0x44/0x60) [<c02f6714>] (kdb_printf) from [<c02fa6f4>] (kdb_main_loop+0xf4/0x6e0) [<c02fa600>] (kdb_main_loop) from [<c02fd5f0>] (kdb_stub+0x268/0x398) [<c02fd388>] (kdb_stub) from [<c02f3ba0>] (kgdb_cpu_enter+0x1f8/0x674) [<c02f39a8>] (kgdb_cpu_enter) from [<c02f4330>] (kgdb_handle_exception+0x1c4/0x1fc) [<c02f416c>] (kgdb_handle_exception) from [<c0210fe0>] (kgdb_compiled_brk_fn+0x30/0x3c) [<c0210fb0>] (kgdb_compiled_brk_fn) from [<c020d7ac>] (do_undefinstr+0x180/0x1a0) [<c020d62c>] (do_undefinstr) from [<c0201b44>] (__und_svc_finish+0x0/0x3c) ... [<c02f3224>] (kgdb_breakpoint) from [<c02f3310>] (sysrq_handle_dbg+0x58/0x6c) [<c02f32b8>] (sysrq_handle_dbg) from [<c062abf0>] (__handle_sysrq+0xac/0x154) Let's disable this warning when we're in kgdb to avoid the spew. The whole system is stopped when we're in kgdb so we can't exactly wait for someone else to drop the lock. Presumably the best we can do is to disable the warning and hope for the best. Fixes: ddde3c18b700 ("vt: More locking checks") Cc: Daniel Vetter <daniel.vetter@intel.com> Signed-off-by: Douglas Anderson <dianders@chromium.org> Link: https://lore.kernel.org/r/20190725183551.169208-1-dianders@chromium.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers')
-rw-r--r--drivers/tty/serial/kgdboc.c4
1 files changed, 4 insertions, 0 deletions
diff --git a/drivers/tty/serial/kgdboc.c b/drivers/tty/serial/kgdboc.c
index bfe5e9e034ec..c7d51b51898f 100644
--- a/drivers/tty/serial/kgdboc.c
+++ b/drivers/tty/serial/kgdboc.c
@@ -277,10 +277,14 @@ static void kgdboc_pre_exp_handler(void)
/* Increment the module count when the debugger is active */
if (!kgdb_connected)
try_module_get(THIS_MODULE);
+
+ atomic_inc(&ignore_console_lock_warning);
}
static void kgdboc_post_exp_handler(void)
{
+ atomic_dec(&ignore_console_lock_warning);
+
/* decrement the module count when the debugger detaches */
if (!kgdb_connected)
module_put(THIS_MODULE);