There are instances where rcu_cpu_stall_reset() is called when jiffies
did not get a chance to update for a long time. Before jiffies is
updated, the CPU stall detector can go off triggering false-positives
where a just-started grace period appears to be ages old. In the past,
we disabled stall detection in rcu_cpu_stall_reset() however this got
changed [1]. This is resulting in false-positives in KGDB usecase [2].
Fix this by deferring the update of jiffies to the third run of the FQS
loop. This is more robust, as, even if rcu_cpu_stall_reset() is called
just before jiffies is read, we would end up pushing out the jiffies
read by 3 more FQS loops. Meanwhile the CPU stall detection will be
delayed and we will not get any false positives.
[1] https://lore.kernel.org/all/20210521155624.174524-2-senozhatsky@chromium.or…
[2] https://lore.kernel.org/all/20230814020045.51950-2-chenhuacai@loongson.cn/
Tested with rcutorture.cpu_stall option as well to verify stall behavior
with/without patch.
Tested-by: Huacai Chen <chenhuacai(a)loongson.cn>
Reported-by: Huacai Chen <chenhuacai(a)loongson.cn>
Closes: https://lore.kernel.org/all/20230814020045.51950-2-chenhuacai@loongson.cn/
Suggested-by: Paul McKenney <paulmck(a)kernel.org>
Cc: Sergey Senozhatsky <senozhatsky(a)chromium.org>
Cc: Thomas Gleixner <tglx(a)linutronix.de>
Cc: stable(a)vger.kernel.org
Fixes: a80be428fbc1 ("rcu: Do not disable GP stall detection in rcu_cpu_stall_reset()")
Signed-off-by: Joel Fernandes (Google) <joel(a)joelfernandes.org>
---
kernel/rcu/tree.c | 12 ++++++++++++
kernel/rcu/tree.h | 4 ++++
kernel/rcu/tree_stall.h | 20 ++++++++++++++++++--
3 files changed, 34 insertions(+), 2 deletions(-)
diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index 1449cb69a0e0..b695c0eb515a 100644
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -1552,10 +1552,22 @@ static bool rcu_gp_fqs_check_wake(int *gfp)
*/
static void rcu_gp_fqs(bool first_time)
{
+ int nr_fqs = READ_ONCE(rcu_state.nr_fqs_jiffies_stall);
struct rcu_node *rnp = rcu_get_root();
WRITE_ONCE(rcu_state.gp_activity, jiffies);
WRITE_ONCE(rcu_state.n_force_qs, rcu_state.n_force_qs + 1);
+
+ WARN_ON_ONCE(nr_fqs > 3);
+ /* Only countdown nr_fqs for stall purposes if jiffies moves. */
+ if (nr_fqs) {
+ if (nr_fqs == 1) {
+ WRITE_ONCE(rcu_state.jiffies_stall,
+ jiffies + rcu_jiffies_till_stall_check());
+ }
+ WRITE_ONCE(rcu_state.nr_fqs_jiffies_stall, --nr_fqs);
+ }
+
if (first_time) {
/* Collect dyntick-idle snapshots. */
force_qs_rnp(dyntick_save_progress_counter);
diff --git a/kernel/rcu/tree.h b/kernel/rcu/tree.h
index 192536916f9a..e9821a8422db 100644
--- a/kernel/rcu/tree.h
+++ b/kernel/rcu/tree.h
@@ -386,6 +386,10 @@ struct rcu_state {
/* in jiffies. */
unsigned long jiffies_stall; /* Time at which to check */
/* for CPU stalls. */
+ int nr_fqs_jiffies_stall; /* Number of fqs loops after
+ * which read jiffies and set
+ * jiffies_stall. Stall
+ * warnings disabled if !0. */
unsigned long jiffies_resched; /* Time at which to resched */
/* a reluctant CPU. */
unsigned long n_force_qs_gpstart; /* Snapshot of n_force_qs at */
diff --git a/kernel/rcu/tree_stall.h b/kernel/rcu/tree_stall.h
index b10b8349bb2a..a2fa6b22e248 100644
--- a/kernel/rcu/tree_stall.h
+++ b/kernel/rcu/tree_stall.h
@@ -149,12 +149,17 @@ static void panic_on_rcu_stall(void)
/**
* rcu_cpu_stall_reset - restart stall-warning timeout for current grace period
*
+ * To perform the reset request from the caller, disable stall detection until
+ * 3 fqs loops have passed. This is required to ensure a fresh jiffies is
+ * loaded. It should be safe to do from the fqs loop as enough timer
+ * interrupts and context switches should have passed.
+ *
* The caller must disable hard irqs.
*/
void rcu_cpu_stall_reset(void)
{
- WRITE_ONCE(rcu_state.jiffies_stall,
- jiffies + rcu_jiffies_till_stall_check());
+ WRITE_ONCE(rcu_state.nr_fqs_jiffies_stall, 3);
+ WRITE_ONCE(rcu_state.jiffies_stall, ULONG_MAX);
}
//////////////////////////////////////////////////////////////////////////////
@@ -170,6 +175,7 @@ static void record_gp_stall_check_time(void)
WRITE_ONCE(rcu_state.gp_start, j);
j1 = rcu_jiffies_till_stall_check();
smp_mb(); // ->gp_start before ->jiffies_stall and caller's ->gp_seq.
+ WRITE_ONCE(rcu_state.nr_fqs_jiffies_stall, 0);
WRITE_ONCE(rcu_state.jiffies_stall, j + j1);
rcu_state.jiffies_resched = j + j1 / 2;
rcu_state.n_force_qs_gpstart = READ_ONCE(rcu_state.n_force_qs);
@@ -725,6 +731,16 @@ static void check_cpu_stall(struct rcu_data *rdp)
!rcu_gp_in_progress())
return;
rcu_stall_kick_kthreads();
+
+ /*
+ * Check if it was requested (via rcu_cpu_stall_reset()) that the FQS
+ * loop has to set jiffies to ensure a non-stale jiffies value. This
+ * is required to have good jiffies value after coming out of long
+ * breaks of jiffies updates. Not doing so can cause false positives.
+ */
+ if (READ_ONCE(rcu_state.nr_fqs_jiffies_stall) > 0)
+ return;
+
j = jiffies;
/*
--
2.42.0.rc2.253.gd59a3bf2b4-goog
Dear friend
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communication i have millions of dollars to invest
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In the line 910, the value of m1 may be zero, so there is a possibility
of dividing by zero, we fixed it by checking the values before dividing
(found with SVACE). In the same way, after checking and reading the
function, we found that lines 906, 908, 912 have the same situation, so
we fixed them as well.
Found by Linux Verification Center (linuxtesting.org) with SVACE.
Signed-off-by: Rand Deeb <deeb.rand(a)confident.ru>
---
drivers/ssb/main.c | 16 ++++++++++++----
1 file changed, 12 insertions(+), 4 deletions(-)
diff --git a/drivers/ssb/main.c b/drivers/ssb/main.c
index 0a26984acb2c..e0776a16d04d 100644
--- a/drivers/ssb/main.c
+++ b/drivers/ssb/main.c
@@ -903,13 +903,21 @@ u32 ssb_calc_clock_rate(u32 plltype, u32 n, u32 m)
case SSB_CHIPCO_CLK_MC_BYPASS:
return clock;
case SSB_CHIPCO_CLK_MC_M1:
- return (clock / m1);
+ if (m1 != 0)
+ return (clock / m1);
+ break;
case SSB_CHIPCO_CLK_MC_M1M2:
- return (clock / (m1 * m2));
+ if ((m1 * m2) != 0)
+ return (clock / (m1 * m2));
+ break;
case SSB_CHIPCO_CLK_MC_M1M2M3:
- return (clock / (m1 * m2 * m3));
+ if ((m1 * m2 * m3) != 0)
+ return (clock / (m1 * m2 * m3));
+ break;
case SSB_CHIPCO_CLK_MC_M1M3:
- return (clock / (m1 * m3));
+ if ((m1 * m3) != 0)
+ return (clock / (m1 * m3));
+ break;
}
return 0;
case SSB_PLLTYPE_2:
--
2.34.1
v1 -> v2:
- Address the comment to reduce size of queue pointer from queue size
- Consider the data size during memcpy to avoid OOB write
- Use hweight_long() to count the setbits representing the supported codecs
v1: https://lore.kernel.org/all/1690432469-14803-1-git-send-email-quic_vgarodia…
This series primarily adds check at relevant places in venus driver where there are possible OOB
accesses due to unexpected payload from venus firmware. The patches describes the specific OOB
possibility.
Please review and share your feedback.
Vikash Garodia (4):
venus: hfi: add checks to perform sanity on queue pointers
venus: hfi: fix the check to handle session buffer requirement
venus: hfi: add checks to handle capabilities from firmware
venus: hfi_parser: Add check to keep the number of codecs within range
drivers/media/platform/qcom/venus/hfi_msgs.c | 2 +-
drivers/media/platform/qcom/venus/hfi_parser.c | 15 +++++++++++++++
drivers/media/platform/qcom/venus/hfi_venus.c | 10 ++++++++++
3 files changed, 26 insertions(+), 1 deletion(-)
--
2.7.4
From: Krzysztof Kozlowski <krzysztof.kozlowski(a)linaro.org>
[ Upstream commit 8183bb7e291b7818f49ea39687c2fafa01a46e27 ]
GPIO_ACTIVE_x flags are not correct in the context of interrupt flags.
These are simple defines so they could be used in DTS but they will not
have the same meaning: GPIO_ACTIVE_HIGH = 0 = IRQ_TYPE_NONE.
Correct the interrupt flags, assuming the author of the code wanted same
logical behavior behind the name "ACTIVE_xxx", this is:
ACTIVE_HIGH => IRQ_TYPE_LEVEL_HIGH
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski(a)linaro.org>
Link: https://lore.kernel.org/r/20230707063335.13317-1-krzysztof.kozlowski@linaro…
Signed-off-by: Heiko Stuebner <heiko(a)sntech.de>
Signed-off-by: Sasha Levin <sashal(a)kernel.org>
---
arch/arm64/boot/dts/rockchip/rk3399-eaidk-610.dts | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/arm64/boot/dts/rockchip/rk3399-eaidk-610.dts b/arch/arm64/boot/dts/rockchip/rk3399-eaidk-610.dts
index d1f343345f674..6464ef4d113dd 100644
--- a/arch/arm64/boot/dts/rockchip/rk3399-eaidk-610.dts
+++ b/arch/arm64/boot/dts/rockchip/rk3399-eaidk-610.dts
@@ -773,7 +773,7 @@ brcmf: wifi@1 {
compatible = "brcm,bcm4329-fmac";
reg = <1>;
interrupt-parent = <&gpio0>;
- interrupts = <RK_PA3 GPIO_ACTIVE_HIGH>;
+ interrupts = <RK_PA3 IRQ_TYPE_LEVEL_HIGH>;
interrupt-names = "host-wake";
pinctrl-names = "default";
pinctrl-0 = <&wifi_host_wake_l>;
--
2.40.1