From e9e1b20fae7de06ba36dd3f8dba858157bad233d Mon Sep 17 00:00:00 2001 From: Mika Westerberg Date: Wed, 25 Sep 2024 12:59:20 +0300 Subject: [PATCH 1/2] thunderbolt: Fix KASAN reported stack out-of-bounds read in tb_retimer_scan() KASAN reported following issue: BUG: KASAN: stack-out-of-bounds in tb_retimer_scan+0xffe/0x1550 [thunderbolt] Read of size 4 at addr ffff88810111fc1c by task kworker/u56:0/11 CPU: 0 UID: 0 PID: 11 Comm: kworker/u56:0 Tainted: G U 6.11.0+ #1387 Tainted: [U]=USER Workqueue: thunderbolt0 tb_handle_hotplug [thunderbolt] Call Trace: dump_stack_lvl+0x6c/0x90 print_report+0xd1/0x630 kasan_report+0xdb/0x110 __asan_report_load4_noabort+0x14/0x20 tb_retimer_scan+0xffe/0x1550 [thunderbolt] tb_scan_port+0xa6f/0x2060 [thunderbolt] tb_handle_hotplug+0x17b1/0x3080 [thunderbolt] process_one_work+0x626/0x1100 worker_thread+0x6c8/0xfa0 kthread+0x2c8/0x3a0 ret_from_fork+0x3a/0x80 ret_from_fork_asm+0x1a/0x30 This happens because the loop variable still gets incremented by one so max becomes 3 instead of 2, and this makes the second loop read past the the array declared on the stack. Fix this by assigning to max directly in the loop body. Fixes: ff6ab055e070 ("thunderbolt: Add receiver lane margining support for retimers") CC: stable@vger.kernel.org Signed-off-by: Mika Westerberg --- drivers/thunderbolt/retimer.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/drivers/thunderbolt/retimer.c b/drivers/thunderbolt/retimer.c index 721319329afa..7db9869a9f3f 100644 --- a/drivers/thunderbolt/retimer.c +++ b/drivers/thunderbolt/retimer.c @@ -516,7 +516,7 @@ int tb_retimer_scan(struct tb_port *port, bool add) */ tb_retimer_set_inbound_sbtx(port); - for (i = 1; i <= TB_MAX_RETIMER_INDEX; i++) { + for (max = 1, i = 1; i <= TB_MAX_RETIMER_INDEX; i++) { /* * Last retimer is true only for the last on-board * retimer (the one connected directly to the Type-C @@ -527,9 +527,10 @@ int tb_retimer_scan(struct tb_port *port, bool add) last_idx = i; else if (ret < 0) break; + + max = i; } - max = i; ret = 0; /* Add retimers if they do not exist already */ From 3cea8af2d1a9ae5869b47c3dabe3b20f331f3bbd Mon Sep 17 00:00:00 2001 From: Gil Fine Date: Thu, 10 Oct 2024 17:29:42 +0300 Subject: [PATCH 2/2] thunderbolt: Honor TMU requirements in the domain when setting TMU mode Currently, when configuring TMU (Time Management Unit) mode of a given router, we take into account only its own TMU requirements ignoring other routers in the domain. This is problematic if the router we are configuring has lower TMU requirements than what is already configured in the domain. In the scenario below, we have a host router with two USB4 ports: A and B. Port A connected to device router #1 (which supports CL states) and existing DisplayPort tunnel, thus, the TMU mode is HiFi uni-directional. 1. Initial topology [Host] A/ / [Device #1] / Monitor 2. Plug in device #2 (that supports CL states) to downstream port B of the host router [Host] A/ B\ / \ [Device #1] [Device #2] / Monitor The TMU mode on port B and port A will be configured to LowRes which is not what we want and will cause monitor to start flickering. To address this we first scan the domain and search for any router configured to HiFi uni-directional mode, and if found, configure TMU mode of the given router to HiFi uni-directional as well. Cc: stable@vger.kernel.org Signed-off-by: Gil Fine Signed-off-by: Mika Westerberg --- drivers/thunderbolt/tb.c | 48 +++++++++++++++++++++++++++++++++++----- 1 file changed, 42 insertions(+), 6 deletions(-) diff --git a/drivers/thunderbolt/tb.c b/drivers/thunderbolt/tb.c index 10e719dd837c..4f777788e917 100644 --- a/drivers/thunderbolt/tb.c +++ b/drivers/thunderbolt/tb.c @@ -288,6 +288,24 @@ static void tb_increase_tmu_accuracy(struct tb_tunnel *tunnel) device_for_each_child(&sw->dev, NULL, tb_increase_switch_tmu_accuracy); } +static int tb_switch_tmu_hifi_uni_required(struct device *dev, void *not_used) +{ + struct tb_switch *sw = tb_to_switch(dev); + + if (sw && tb_switch_tmu_is_enabled(sw) && + tb_switch_tmu_is_configured(sw, TB_SWITCH_TMU_MODE_HIFI_UNI)) + return 1; + + return device_for_each_child(dev, NULL, + tb_switch_tmu_hifi_uni_required); +} + +static bool tb_tmu_hifi_uni_required(struct tb *tb) +{ + return device_for_each_child(&tb->dev, NULL, + tb_switch_tmu_hifi_uni_required) == 1; +} + static int tb_enable_tmu(struct tb_switch *sw) { int ret; @@ -302,12 +320,30 @@ static int tb_enable_tmu(struct tb_switch *sw) ret = tb_switch_tmu_configure(sw, TB_SWITCH_TMU_MODE_MEDRES_ENHANCED_UNI); if (ret == -EOPNOTSUPP) { - if (tb_switch_clx_is_enabled(sw, TB_CL1)) - ret = tb_switch_tmu_configure(sw, - TB_SWITCH_TMU_MODE_LOWRES); - else - ret = tb_switch_tmu_configure(sw, - TB_SWITCH_TMU_MODE_HIFI_BI); + if (tb_switch_clx_is_enabled(sw, TB_CL1)) { + /* + * Figure out uni-directional HiFi TMU requirements + * currently in the domain. If there are no + * uni-directional HiFi requirements we can put the TMU + * into LowRes mode. + * + * Deliberately skip bi-directional HiFi links + * as these work independently of other links + * (and they do not allow any CL states anyway). + */ + if (tb_tmu_hifi_uni_required(sw->tb)) + ret = tb_switch_tmu_configure(sw, + TB_SWITCH_TMU_MODE_HIFI_UNI); + else + ret = tb_switch_tmu_configure(sw, + TB_SWITCH_TMU_MODE_LOWRES); + } else { + ret = tb_switch_tmu_configure(sw, TB_SWITCH_TMU_MODE_HIFI_BI); + } + + /* If not supported, fallback to bi-directional HiFi */ + if (ret == -EOPNOTSUPP) + ret = tb_switch_tmu_configure(sw, TB_SWITCH_TMU_MODE_HIFI_BI); } if (ret) return ret;