[PATCH 5.15 0/9] 5.15.130-rc1 review

[PATCH 5.15 0/9] 5.15.130-rc1 review

[Greg Kroah-Hartman]

This is the start of the stable review cycle for the 5.15.130 release.
There are 9 patches in this series, all will be posted as a response
to this one.  If anyone has any issues with these being applied, please
let me know.

Responses should be made by Sat, 02 Sep 2023 11:08:22 +0000.
Anything received after that time might be too late.

The whole patch series can be found in one patch at:
	https://www.kernel.org/pub/linux/kernel/v5.x/stable-review/patch-5.15.130-rc1.gz
or in the git tree and branch at:
	git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable-rc.git linux-5.15.y
and the diffstat can be found below.

thanks,

greg k-h

-------------
Pseudo-Shortlog of commits:

Greg Kroah-Hartman <gregkh@linuxfoundation.org>
    Linux 5.15.130-rc1

Paul E. McKenney <paulmck@kernel.org>
    rcu-tasks: Add trc_inspect_reader() checks for exiting critical section

Paul E. McKenney <paulmck@kernel.org>
    rcu-tasks: Wait for trc_read_check_handler() IPIs

Neeraj Upadhyay <neeraju@codeaurora.org>
    rcu-tasks: Fix IPI failure handling in trc_wait_for_one_reader

Paul E. McKenney <paulmck@kernel.org>
    rcu: Prevent expedited GP from enabling tick on offline CPU

James Morse <james.morse@arm.com>
    ARM: module: Use module_init_layout_section() to spot init sections

James Morse <james.morse@arm.com>
    arm64: module: Use module_init_layout_section() to spot init sections

Arnd Bergmann <arnd@arndb.de>
    arm64: module-plts: inline linux/moduleloader.h

James Morse <james.morse@arm.com>
    module: Expose module_init_layout_section()

Mario Limonciello <mario.limonciello@amd.com>
    ACPI: thermal: Drop nocrt parameter


-------------

Diffstat:

 Documentation/admin-guide/kernel-parameters.txt |  4 ---
 Makefile                                        |  4 +--
 arch/arm/kernel/module-plts.c                   |  2 +-
 arch/arm64/kernel/module-plts.c                 |  3 ++-
 drivers/acpi/thermal.c                          |  6 +----
 include/linux/moduleloader.h                    |  5 ++++
 kernel/module.c                                 |  2 +-
 kernel/rcu/tasks.h                              | 36 ++++++++++++++++++-------
 kernel/rcu/tree_exp.h                           |  5 +++-
 9 files changed, 42 insertions(+), 25 deletions(-)

[PATCH 5.15 1/9] ACPI: thermal: Drop nocrt parameter

[Greg Kroah-Hartman]

5.15-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Mario Limonciello <mario.limonciello@amd.com>

commit 5f641174a12b8a876a4101201a21ef4675ecc014 upstream.

The `nocrt` module parameter has no code associated with it and does
nothing.  As `crt=-1` has same functionality as what nocrt should be
doing drop `nocrt` and associated documentation.

This should fix a quirk for Gigabyte GA-7ZX that used `nocrt` and
thus didn't function properly.

Fixes: 8c99fdce3078 ("ACPI: thermal: set "thermal.nocrt" via DMI on Gigabyte GA-7ZX")
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
Cc: All applicable <stable@vger.kernel.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 Documentation/admin-guide/kernel-parameters.txt |    4 ----
 drivers/acpi/thermal.c                          |    6 +-----
 2 files changed, 1 insertion(+), 9 deletions(-)

--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -5770,10 +5770,6 @@
 			-1: disable all critical trip points in all thermal zones
 			<degrees C>: override all critical trip points
 
-	thermal.nocrt=	[HW,ACPI]
-			Set to disable actions on ACPI thermal zone
-			critical and hot trip points.
-
 	thermal.off=	[HW,ACPI]
 			1: disable ACPI thermal control
 
--- a/drivers/acpi/thermal.c
+++ b/drivers/acpi/thermal.c
@@ -59,10 +59,6 @@ static int tzp;
 module_param(tzp, int, 0444);
 MODULE_PARM_DESC(tzp, "Thermal zone polling frequency, in 1/10 seconds.");
 
-static int nocrt;
-module_param(nocrt, int, 0);
-MODULE_PARM_DESC(nocrt, "Set to take no action upon ACPI thermal zone critical trips points.");
-
 static int off;
 module_param(off, int, 0);
 MODULE_PARM_DESC(off, "Set to disable ACPI thermal support.");
@@ -1132,7 +1128,7 @@ static int thermal_nocrt(const struct dm
 
 	pr_notice("%s detected: disabling all critical thermal trip point actions.\n",
 		  d->ident);
-	nocrt = 1;
+	crt = -1;
 	return 0;
 }
 static int thermal_tzp(const struct dmi_system_id *d) {

[PATCH 5.15 2/9] module: Expose module_init_layout_section()

[Greg Kroah-Hartman]

5.15-stable review patch.  If anyone has any objections, please let me know.

------------------

From: James Morse <james.morse@arm.com>

commit 2abcc4b5a64a65a2d2287ba0be5c2871c1552416 upstream.

module_init_layout_section() choses whether the core module loader
considers a section as init or not. This affects the placement of the
exit section when module unloading is disabled. This code will never run,
so it can be free()d once the module has been initialised.

arm and arm64 need to count the number of PLTs they need before applying
relocations based on the section name. The init PLTs are stored separately
so they can be free()d. arm and arm64 both use within_module_init() to
decide which list of PLTs to use when applying the relocation.

Because within_module_init()'s behaviour changes when module unloading
is disabled, both architecture would need to take this into account when
counting the PLTs.

Today neither architecture does this, meaning when module unloading is
disabled there are insufficient PLTs in the init section to load some
modules, resulting in warnings:
| WARNING: CPU: 2 PID: 51 at arch/arm64/kernel/module-plts.c:99 module_emit_plt_entry+0x184/0x1cc
| Modules linked in: crct10dif_common
| CPU: 2 PID: 51 Comm: modprobe Not tainted 6.5.0-rc4-yocto-standard-dirty #15208
| Hardware name: QEMU KVM Virtual Machine, BIOS 0.0.0 02/06/2015
| pstate: 20400005 (nzCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
| pc : module_emit_plt_entry+0x184/0x1cc
| lr : module_emit_plt_entry+0x94/0x1cc
| sp : ffffffc0803bba60
[...]
| Call trace:
|  module_emit_plt_entry+0x184/0x1cc
|  apply_relocate_add+0x2bc/0x8e4
|  load_module+0xe34/0x1bd4
|  init_module_from_file+0x84/0xc0
|  __arm64_sys_finit_module+0x1b8/0x27c
|  invoke_syscall.constprop.0+0x5c/0x104
|  do_el0_svc+0x58/0x160
|  el0_svc+0x38/0x110
|  el0t_64_sync_handler+0xc0/0xc4
|  el0t_64_sync+0x190/0x194

Instead of duplicating module_init_layout_section()s logic, expose it.

Reported-by: Adam Johnston <adam.johnston@arm.com>
Fixes: 055f23b74b20 ("module: check for exit sections in layout_sections() instead of module_init_section()")
Cc: stable@vger.kernel.org
Signed-off-by: James Morse <james.morse@arm.com>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 include/linux/moduleloader.h |    5 +++++
 kernel/module.c              |    2 +-
 2 files changed, 6 insertions(+), 1 deletion(-)

--- a/include/linux/moduleloader.h
+++ b/include/linux/moduleloader.h
@@ -39,6 +39,11 @@ bool module_init_section(const char *nam
  */
 bool module_exit_section(const char *name);
 
+/* Describes whether within_module_init() will consider this an init section
+ * or not. This behaviour changes with CONFIG_MODULE_UNLOAD.
+ */
+bool module_init_layout_section(const char *sname);
+
 /*
  * Apply the given relocation to the (simplified) ELF.  Return -error
  * or 0.
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -2407,7 +2407,7 @@ static long get_offset(struct module *mo
 	return ret;
 }
 
-static bool module_init_layout_section(const char *sname)
+bool module_init_layout_section(const char *sname)
 {
 #ifndef CONFIG_MODULE_UNLOAD
 	if (module_exit_section(sname))

[PATCH 5.15 3/9] arm64: module-plts: inline linux/moduleloader.h

[Greg Kroah-Hartman]

5.15-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Arnd Bergmann <arnd@arndb.de>

commit 60a0aab7463ee69296692d980b96510ccce3934e upstream.

module_frob_arch_sections() is declared in moduleloader.h, but
that is not included before the definition:

arch/arm64/kernel/module-plts.c:286:5: error: no previous prototype for 'module_frob_arch_sections' [-Werror=missing-prototypes]

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Kees Cook <keescook@chromium.org>
Acked-by: Ard Biesheuvel <ardb@kernel.org>
Link: https://lore.kernel.org/r/20230516160642.523862-11-arnd@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 arch/arm64/kernel/module-plts.c |    1 +
 1 file changed, 1 insertion(+)

--- a/arch/arm64/kernel/module-plts.c
+++ b/arch/arm64/kernel/module-plts.c
@@ -7,6 +7,7 @@
 #include <linux/ftrace.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
+#include <linux/moduleloader.h>
 #include <linux/sort.h>
 
 static struct plt_entry __get_adrp_add_pair(u64 dst, u64 pc,

[PATCH 5.15 4/9] arm64: module: Use module_init_layout_section() to spot init sections

[Greg Kroah-Hartman]

5.15-stable review patch.  If anyone has any objections, please let me know.

------------------

From: James Morse <james.morse@arm.com>

commit f928f8b1a2496e7af95b860f9acf553f20f68f16 upstream.

Today module_frob_arch_sections() spots init sections from their
'init' prefix, and uses this to keep the init PLTs separate from the rest.

module_emit_plt_entry() uses within_module_init() to determine if a
location is in the init text or not, but this depends on whether
core code thought this was an init section.

Naturally the logic is different.

module_init_layout_section() groups the init and exit text together if
module unloading is disabled, as the exit code will never run. The result
is kernels with this configuration can't load all their modules because
there are not enough PLTs for the combined init+exit section.

This results in the following:
| WARNING: CPU: 2 PID: 51 at arch/arm64/kernel/module-plts.c:99 module_emit_plt_entry+0x184/0x1cc
| Modules linked in: crct10dif_common
| CPU: 2 PID: 51 Comm: modprobe Not tainted 6.5.0-rc4-yocto-standard-dirty #15208
| Hardware name: QEMU KVM Virtual Machine, BIOS 0.0.0 02/06/2015
| pstate: 20400005 (nzCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
| pc : module_emit_plt_entry+0x184/0x1cc
| lr : module_emit_plt_entry+0x94/0x1cc
| sp : ffffffc0803bba60
[...]
| Call trace:
|  module_emit_plt_entry+0x184/0x1cc
|  apply_relocate_add+0x2bc/0x8e4
|  load_module+0xe34/0x1bd4
|  init_module_from_file+0x84/0xc0
|  __arm64_sys_finit_module+0x1b8/0x27c
|  invoke_syscall.constprop.0+0x5c/0x104
|  do_el0_svc+0x58/0x160
|  el0_svc+0x38/0x110
|  el0t_64_sync_handler+0xc0/0xc4
|  el0t_64_sync+0x190/0x194

A previous patch exposed module_init_layout_section(), use that so the
logic is the same.

Reported-by: Adam Johnston <adam.johnston@arm.com>
Tested-by: Adam Johnston <adam.johnston@arm.com>
Fixes: 055f23b74b20 ("module: check for exit sections in layout_sections() instead of module_init_section()")
Cc: <stable@vger.kernel.org> # 5.15.x: 60a0aab7463ee69 arm64: module-plts: inline linux/moduleloader.h
Cc: <stable@vger.kernel.org> # 5.15.x
Signed-off-by: James Morse <james.morse@arm.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 arch/arm64/kernel/module-plts.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/arch/arm64/kernel/module-plts.c
+++ b/arch/arm64/kernel/module-plts.c
@@ -343,7 +343,7 @@ int module_frob_arch_sections(Elf_Ehdr *
 		if (nents)
 			sort(rels, nents, sizeof(Elf64_Rela), cmp_rela, NULL);
 
-		if (!str_has_prefix(secstrings + dstsec->sh_name, ".init"))
+		if (!module_init_layout_section(secstrings + dstsec->sh_name))
 			core_plts += count_plts(syms, rels, numrels,
 						sechdrs[i].sh_info, dstsec);
 		else

[PATCH 5.15 5/9] ARM: module: Use module_init_layout_section() to spot init sections

[Greg Kroah-Hartman]

5.15-stable review patch.  If anyone has any objections, please let me know.

------------------

From: James Morse <james.morse@arm.com>

commit a6846234f45801441f0e31a8b37f901ef0abd2df upstream.

Today module_frob_arch_sections() spots init sections from their
'init' prefix, and uses this to keep the init PLTs separate from the rest.

get_module_plt() uses within_module_init() to determine if a
location is in the init text or not, but this depends on whether
core code thought this was an init section.

Naturally the logic is different.

module_init_layout_section() groups the init and exit text together if
module unloading is disabled, as the exit code will never run. The result
is kernels with this configuration can't load all their modules because
there are not enough PLTs for the combined init+exit section.

A previous patch exposed module_init_layout_section(), use that so the
logic is the same.

Fixes: 055f23b74b20 ("module: check for exit sections in layout_sections() instead of module_init_section()")
Cc: stable@vger.kernel.org
Signed-off-by: James Morse <james.morse@arm.com>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 arch/arm/kernel/module-plts.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/arch/arm/kernel/module-plts.c
+++ b/arch/arm/kernel/module-plts.c
@@ -256,7 +256,7 @@ int module_frob_arch_sections(Elf_Ehdr *
 		/* sort by type and symbol index */
 		sort(rels, numrels, sizeof(Elf32_Rel), cmp_rel, NULL);
 
-		if (strncmp(secstrings + dstsec->sh_name, ".init", 5) != 0)
+		if (!module_init_layout_section(secstrings + dstsec->sh_name))
 			core_plts += count_plts(syms, dstsec->sh_addr, rels,
 						numrels, s->sh_info);
 		else

[PATCH 5.15 6/9] rcu: Prevent expedited GP from enabling tick on offline CPU

[Greg Kroah-Hartman]

5.15-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Paul E. McKenney <paulmck@kernel.org>

commit 147f04b14adde831eb4a0a1e378667429732f9e8 upstream.

If an RCU expedited grace period starts just when a CPU is in the process
of going offline, so that the outgoing CPU has completed its pass through
stop-machine but has not yet completed its final dive into the idle loop,
RCU will attempt to enable that CPU's scheduling-clock tick via a call
to tick_dep_set_cpu().  For this to happen, that CPU has to have been
online when the expedited grace period completed its CPU-selection phase.

This is pointless:  The outgoing CPU has interrupts disabled, so it cannot
take a scheduling-clock tick anyway.  In addition, the tick_dep_set_cpu()
function's eventual call to irq_work_queue_on() will splat as follows:

smpboot: CPU 1 is now offline
WARNING: CPU: 6 PID: 124 at kernel/irq_work.c:95
+irq_work_queue_on+0x57/0x60
Modules linked in:
CPU: 6 PID: 124 Comm: kworker/6:2 Not tainted 5.15.0-rc1+ #3
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS
+rel-1.14.0-0-g155821a-rebuilt.opensuse.org 04/01/2014
Workqueue: rcu_gp wait_rcu_exp_gp
RIP: 0010:irq_work_queue_on+0x57/0x60
Code: 8b 05 1d c7 ea 62 a9 00 00 f0 00 75 21 4c 89 ce 44 89 c7 e8
+9b 37 fa ff ba 01 00 00 00 89 d0 c3 4c 89 cf e8 3b ff ff ff eb ee <0f> 0b eb b7
+0f 0b eb db 90 48 c7 c0 98 2a 02 00 65 48 03 05 91
 6f
RSP: 0000:ffffb12cc038fe48 EFLAGS: 00010282
RAX: 0000000000000001 RBX: 0000000000005208 RCX: 0000000000000020
RDX: 0000000000000001 RSI: 0000000000000001 RDI: ffff9ad01f45a680
RBP: 000000000004c990 R08: 0000000000000001 R09: ffff9ad01f45a680
R10: ffffb12cc0317db0 R11: 0000000000000001 R12: 00000000fffecee8
R13: 0000000000000001 R14: 0000000000026980 R15: ffffffff9e53ae00
FS:  0000000000000000(0000) GS:ffff9ad01f580000(0000)
+knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 000000000de0c000 CR4: 00000000000006e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 tick_nohz_dep_set_cpu+0x59/0x70
 rcu_exp_wait_wake+0x54e/0x870
 ? sync_rcu_exp_select_cpus+0x1fc/0x390
 process_one_work+0x1ef/0x3c0
 ? process_one_work+0x3c0/0x3c0
 worker_thread+0x28/0x3c0
 ? process_one_work+0x3c0/0x3c0
 kthread+0x115/0x140
 ? set_kthread_struct+0x40/0x40
 ret_from_fork+0x22/0x30
---[ end trace c5bf75eb6aa80bc6 ]---

This commit therefore avoids invoking tick_dep_set_cpu() on offlined
CPUs to limit both futility and false-positive splats.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 kernel/rcu/tree_exp.h |    5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

--- a/kernel/rcu/tree_exp.h
+++ b/kernel/rcu/tree_exp.h
@@ -507,7 +507,10 @@ static void synchronize_rcu_expedited_wa
 				if (rdp->rcu_forced_tick_exp)
 					continue;
 				rdp->rcu_forced_tick_exp = true;
-				tick_dep_set_cpu(cpu, TICK_DEP_BIT_RCU_EXP);
+				preempt_disable();
+				if (cpu_online(cpu))
+					tick_dep_set_cpu(cpu, TICK_DEP_BIT_RCU_EXP);
+				preempt_enable();
 			}
 		}
 		j = READ_ONCE(jiffies_till_first_fqs);

[PATCH 5.15 7/9] rcu-tasks: Fix IPI failure handling in trc_wait_for_one_reader

[Greg Kroah-Hartman]

5.15-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Neeraj Upadhyay <neeraju@codeaurora.org>

commit 46aa886c483f57ef13cd5ea0a85e70b93eb1d381 upstream.

The trc_wait_for_one_reader() function is called at multiple stages
of trace rcu-tasks GP function, rcu_tasks_wait_gp():

- First, it is called as part of per task function -
  rcu_tasks_trace_pertask(), for all non-idle tasks. As part of per task
  processing, this function add the task in the holdout list and if the
  task is currently running on a CPU, it sends IPI to the task's CPU.
  The IPI handler takes action depending on whether task is in trace
  rcu-tasks read side critical section or not:

  - a. If the task is in trace rcu-tasks read side critical section
       (t->trc_reader_nesting != 0), the IPI handler sets the task's
       ->trc_reader_special.b.need_qs, so that this task notifies exit
       from its outermost read side critical section (by decrementing
       trc_n_readers_need_end) to the GP handling function.
       trc_wait_for_one_reader() also increments trc_n_readers_need_end,
       so that the trace rcu-tasks GP handler function waits for this
       task's read side exit notification. The IPI handler also sets
       t->trc_reader_checked to true, and no further IPIs are sent for
       this task, for this trace rcu-tasks grace period and this
       task can be removed from holdout list.

  - b. If the task is in the process of exiting its trace rcu-tasks
       read side critical section, (t->trc_reader_nesting < 0), defer
       this task's processing to future calls to trc_wait_for_one_reader().

  - c. If task is not in rcu-task read side critical section,
       t->trc_reader_nesting == 0, ->trc_reader_checked is set for this
       task, so that this task is removed from holdout list.

- Second, trc_wait_for_one_reader() is called as part of post scan, in
  function rcu_tasks_trace_postscan(), for all idle tasks.

- Third, in function check_all_holdout_tasks_trace(), this function is
  called for each task in the holdout list, but only if there isn't
  a pending IPI for the task (->trc_ipi_to_cpu == -1). This function
  removed the task from holdout list, if IPI handler has completed the
  required work, to ensure that the current trace rcu-tasks grace period
  either waits for this task, or this task is not in a trace rcu-tasks
  read side critical section.

Now, considering the scenario where smp_call_function_single() fails in
first case, inside rcu_tasks_trace_pertask(). In this case,
->trc_ipi_to_cpu is set to the current CPU for that task. This will
result in trc_wait_for_one_reader() getting skipped in third case,
inside check_all_holdout_tasks_trace(), for this task. This further
results in ->trc_reader_checked never getting set for this task,
and the task not getting removed from holdout list. This can cause
the current trace rcu-tasks grace period to stall.

Fix the above problem, by resetting ->trc_ipi_to_cpu to -1, on
smp_call_function_single() failure, so that future IPI calls can
be send for this task.

Note that all three of the trc_wait_for_one_reader() function's
callers (rcu_tasks_trace_pertask(), rcu_tasks_trace_postscan(),
check_all_holdout_tasks_trace()) hold cpu_read_lock().  This means
that smp_call_function_single() cannot race with CPU hotplug, and thus
should never fail.  Therefore, also add a warning in order to report
any such failure in case smp_call_function_single() grows some other
reason for failure.

Signed-off-by: Neeraj Upadhyay <neeraju@codeaurora.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Cc: Joel Fernandes <joel@joelfernandes.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 kernel/rcu/tasks.h |    4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

--- a/kernel/rcu/tasks.h
+++ b/kernel/rcu/tasks.h
@@ -1041,9 +1041,11 @@ static void trc_wait_for_one_reader(stru
 		if (smp_call_function_single(cpu, trc_read_check_handler, t, 0)) {
 			// Just in case there is some other reason for
 			// failure than the target CPU being offline.
+			WARN_ONCE(1, "%s():  smp_call_function_single() failed for CPU: %d\n",
+				  __func__, cpu);
 			rcu_tasks_trace.n_ipis_fails++;
 			per_cpu(trc_ipi_to_cpu, cpu) = false;
-			t->trc_ipi_to_cpu = cpu;
+			t->trc_ipi_to_cpu = -1;
 		}
 	}
 }

[PATCH 5.15 8/9] rcu-tasks: Wait for trc_read_check_handler() IPIs

[Greg Kroah-Hartman]

5.15-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Paul E. McKenney <paulmck@kernel.org>

commit cbe0d8d91415c9692fe88191940d98952b6855d9 upstream.

Currently, RCU Tasks Trace initializes the trc_n_readers_need_end counter
to the value one, increments it before each trc_read_check_handler()
IPI, then decrements it within trc_read_check_handler() if the target
task was in a quiescent state (or if the target task moved to some other
CPU while the IPI was in flight), complaining if the new value was zero.
The rationale for complaining is that the initial value of one must be
decremented away before zero can be reached, and this decrement has not
yet happened.

Except that trc_read_check_handler() is initiated with an asynchronous
smp_call_function_single(), which might be significantly delayed.  This
can result in false-positive complaints about the counter reaching zero.

This commit therefore waits for in-flight IPI handlers to complete before
decrementing away the initial value of one from the trc_n_readers_need_end
counter.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Cc: Joel Fernandes <joel@joelfernandes.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 kernel/rcu/tasks.h |   14 ++++++++++++++
 1 file changed, 14 insertions(+)

--- a/kernel/rcu/tasks.h
+++ b/kernel/rcu/tasks.h
@@ -1166,14 +1166,28 @@ static void check_all_holdout_tasks_trac
 	}
 }
 
+static void rcu_tasks_trace_empty_fn(void *unused)
+{
+}
+
 /* Wait for grace period to complete and provide ordering. */
 static void rcu_tasks_trace_postgp(struct rcu_tasks *rtp)
 {
+	int cpu;
 	bool firstreport;
 	struct task_struct *g, *t;
 	LIST_HEAD(holdouts);
 	long ret;
 
+	// Wait for any lingering IPI handlers to complete.  Note that
+	// if a CPU has gone offline or transitioned to userspace in the
+	// meantime, all IPI handlers should have been drained beforehand.
+	// Yes, this assumes that CPUs process IPIs in order.  If that ever
+	// changes, there will need to be a recheck and/or timed wait.
+	for_each_online_cpu(cpu)
+		if (smp_load_acquire(per_cpu_ptr(&trc_ipi_to_cpu, cpu)))
+			smp_call_function_single(cpu, rcu_tasks_trace_empty_fn, NULL, 1);
+
 	// Remove the safety count.
 	smp_mb__before_atomic();  // Order vs. earlier atomics
 	atomic_dec(&trc_n_readers_need_end);

[PATCH 5.15 9/9] rcu-tasks: Add trc_inspect_reader() checks for exiting critical section

[Greg Kroah-Hartman]

5.15-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Paul E. McKenney <paulmck@kernel.org>

commit 18f08e758f34e6dfe0668bee51bd2af7adacf381 upstream.

Currently, trc_inspect_reader() treats a task exiting its RCU Tasks
Trace read-side critical section the same as being within that critical
section.  However, this can fail because that task might have already
checked its .need_qs field, which means that it might never decrement
the all-important trc_n_readers_need_end counter.  Of course, for that
to happen, the task would need to never again execute an RCU Tasks Trace
read-side critical section, but this really could happen if the system's
last trampoline was removed.  Note that exit from such a critical section
cannot be treated as a quiescent state due to the possibility of nested
critical sections.  This means that if trc_inspect_reader() sees a
negative nesting value, it must set up to try again later.

This commit therefore ignores tasks that are exiting their RCU Tasks
Trace read-side critical sections so that they will be rechecked later.

[ paulmck: Apply feedback from Neeraj Upadhyay and Boqun Feng. ]

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Cc: Joel Fernandes <joel@joelfernandes.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 kernel/rcu/tasks.h |   18 +++++++++---------
 1 file changed, 9 insertions(+), 9 deletions(-)

--- a/kernel/rcu/tasks.h
+++ b/kernel/rcu/tasks.h
@@ -951,7 +951,7 @@ reset_ipi:
 static bool trc_inspect_reader(struct task_struct *t, void *arg)
 {
 	int cpu = task_cpu(t);
-	bool in_qs = false;
+	int nesting;
 	bool ofl = cpu_is_offline(cpu);
 
 	if (task_curr(t)) {
@@ -971,18 +971,18 @@ static bool trc_inspect_reader(struct ta
 		n_heavy_reader_updates++;
 		if (ofl)
 			n_heavy_reader_ofl_updates++;
-		in_qs = true;
+		nesting = 0;
 	} else {
 		// The task is not running, so C-language access is safe.
-		in_qs = likely(!t->trc_reader_nesting);
+		nesting = t->trc_reader_nesting;
 	}
 
-	// Mark as checked so that the grace-period kthread will
-	// remove it from the holdout list.
-	t->trc_reader_checked = true;
-
-	if (in_qs)
-		return true;  // Already in quiescent state, done!!!
+	// If not exiting a read-side critical section, mark as checked
+	// so that the grace-period kthread will remove it from the
+	// holdout list.
+	t->trc_reader_checked = nesting >= 0;
+	if (nesting <= 0)
+		return !nesting;  // If in QS, done, otherwise try again later.
 
 	// The task is in a read-side critical section, so set up its
 	// state so that it will awaken the grace-period kthread upon exit

Re: [PATCH 5.15 0/9] 5.15.130-rc1 review

[Florian Fainelli]

On 8/31/23 04:10, Greg Kroah-Hartman wrote:
> This is the start of the stable review cycle for the 5.15.130 release.
> There are 9 patches in this series, all will be posted as a response
> to this one.  If anyone has any issues with these being applied, please
> let me know.
> 
> Responses should be made by Sat, 02 Sep 2023 11:08:22 +0000.
> Anything received after that time might be too late.
> 
> The whole patch series can be found in one patch at:
> 	https://www.kernel.org/pub/linux/kernel/v5.x/stable-review/patch-5.15.130-rc1.gz
> or in the git tree and branch at:
> 	git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable-rc.git linux-5.15.y
> and the diffstat can be found below.
> 
> thanks,
> 
> greg k-h

On ARCH_BRCMSTB using 32-bit and 64-bit ARM kernels, build tested on 
BMIPS_GENERIC:

Tested-by: Florian Fainelli <florian.fainelli@broadcom.com>
-- 
Florian

Re: [PATCH 5.15 0/9] 5.15.130-rc1 review

[SeongJae Park]

Hello,

On Thu, 31 Aug 2023 13:10:08 +0200 Greg Kroah-Hartman <gregkh@linuxfoundation.org> wrote:

> This is the start of the stable review cycle for the 5.15.130 release.
> There are 9 patches in this series, all will be posted as a response
> to this one.  If anyone has any issues with these being applied, please
> let me know.
> 
> Responses should be made by Sat, 02 Sep 2023 11:08:22 +0000.
> Anything received after that time might be too late.
> 
> The whole patch series can be found in one patch at:
> 	https://www.kernel.org/pub/linux/kernel/v5.x/stable-review/patch-5.15.130-rc1.gz
> or in the git tree and branch at:
> 	git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable-rc.git linux-5.15.y
> and the diffstat can be found below.

This rc kernel passes DAMON functionality test[1] on my test machine.
Attaching the test results summary below.  Please note that I retrieved the
kernel from linux-stable-rc tree[2].

Tested-by: SeongJae Park <sj@kernel.org>

[1] https://github.com/awslabs/damon-tests/tree/next/corr
[2] 46b26da4b872 ("Linux 5.15.130-rc1")

Thanks,
SJ

[...]

---

ok 13 selftests: damon-tests: build_i386_idle_flag.sh
# selftests: damon-tests: build_i386_highpte.sh
# .config:1341:warning: override: reassigning to symbol DAMON
ok 14 selftests: damon-tests: build_i386_highpte.sh
# selftests: damon-tests: build_nomemcg.sh
# .config:1342:warning: override: reassigning to symbol DAMON
# .config:1352:warning: override: reassigning to symbol CGROUPS
ok 15 selftests: damon-tests: build_nomemcg.sh
# kselftest dir '/home/sjpark/damon-tests-cont/linux/tools/testing/selftests/damon-tests' is in dirty state.
# the log is at '/home/sjpark/log'.
 [32m
ok 1 selftests: damon: debugfs_attrs.sh
ok 1 selftests: damon-tests: kunit.sh
ok 2 selftests: damon-tests: huge_count_read_write.sh
ok 3 selftests: damon-tests: buffer_overflow.sh
ok 4 selftests: damon-tests: rm_contexts.sh
ok 5 selftests: damon-tests: record_null_deref.sh
ok 6 selftests: damon-tests: dbgfs_target_ids_read_before_terminate_race.sh
ok 7 selftests: damon-tests: dbgfs_target_ids_pid_leak.sh
ok 8 selftests: damon-tests: damo_tests.sh
ok 9 selftests: damon-tests: masim-record.sh
ok 10 selftests: damon-tests: build_i386.sh
ok 11 selftests: damon-tests: build_m68k.sh
ok 12 selftests: damon-tests: build_arm64.sh
ok 13 selftests: damon-tests: build_i386_idle_flag.sh
ok 14 selftests: damon-tests: build_i386_highpte.sh
ok 15 selftests: damon-tests: build_nomemcg.sh
 [33m
 [92mPASS [39m
_remote_run_corr.sh SUCCESS

Re: [PATCH 5.15 0/9] 5.15.130-rc1 review

[Ron Economos]

On 8/31/23 4:10 AM, Greg Kroah-Hartman wrote:
> This is the start of the stable review cycle for the 5.15.130 release.
> There are 9 patches in this series, all will be posted as a response
> to this one.  If anyone has any issues with these being applied, please
> let me know.
>
> Responses should be made by Sat, 02 Sep 2023 11:08:22 +0000.
> Anything received after that time might be too late.
>
> The whole patch series can be found in one patch at:
> 	https://www.kernel.org/pub/linux/kernel/v5.x/stable-review/patch-5.15.130-rc1.gz
> or in the git tree and branch at:
> 	git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable-rc.git linux-5.15.y
> and the diffstat can be found below.
>
> thanks,
>
> greg k-h

Built and booted successfully on RISC-V RV64 (HiFive Unmatched).

Tested-by: Ron Economos <re@w6rz.net>

Re: [PATCH 5.15 0/9] 5.15.130-rc1 review

[Sudip Mukherjee (Codethink)]

Hi Greg,

On Thu, Aug 31, 2023 at 01:10:08PM +0200, Greg Kroah-Hartman wrote:
> This is the start of the stable review cycle for the 5.15.130 release.
> There are 9 patches in this series, all will be posted as a response
> to this one.  If anyone has any issues with these being applied, please
> let me know.
> 
> Responses should be made by Sat, 02 Sep 2023 11:08:22 +0000.
> Anything received after that time might be too late.

Build test (gcc version 12.3.1 20230829):
mips: 62 configs -> no failure
arm: 99 configs -> no failure
arm64: 3 configs -> no failure
x86_64: 4 configs -> no failure
alpha allmodconfig -> no failure
csky allmodconfig -> no failure
powerpc allmodconfig -> no failure
riscv allmodconfig -> no failure
s390 allmodconfig -> no failure
xtensa allmodconfig -> no failure

Boot test:
x86_64: Booted on my test laptop. No regression.
x86_64: Booted on qemu. No regression. [1]
arm64: Booted on rpi4b (4GB model). No regression. [2]
mips: Booted on ci20 board. No regression. [3]

[1]. https://openqa.qa.codethink.co.uk/tests/4885
[2]. https://openqa.qa.codethink.co.uk/tests/4887
[3]. https://openqa.qa.codethink.co.uk/tests/4886

Tested-by: Sudip Mukherjee <sudip.mukherjee@codethink.co.uk>

-- 
Regards
Sudip

Re: [PATCH 5.15 0/9] 5.15.130-rc1 review

[Naresh Kamboju]

On Thu, 31 Aug 2023 at 16:41, Greg Kroah-Hartman
<gregkh@linuxfoundation.org> wrote:
>
> This is the start of the stable review cycle for the 5.15.130 release.
> There are 9 patches in this series, all will be posted as a response
> to this one.  If anyone has any issues with these being applied, please
> let me know.
>
> Responses should be made by Sat, 02 Sep 2023 11:08:22 +0000.
> Anything received after that time might be too late.
>
> The whole patch series can be found in one patch at:
>         https://www.kernel.org/pub/linux/kernel/v5.x/stable-review/patch-5.15.130-rc1.gz
> or in the git tree and branch at:
>         git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable-rc.git linux-5.15.y
> and the diffstat can be found below.
>
> thanks,
>
> greg k-h

Results from Linaro’s test farm.
No regressions on arm64, arm, x86_64, and i386.

Tested-by: Linux Kernel Functional Testing <lkft@linaro.org>

## Build
* kernel: 5.15.130-rc1
* git: https://gitlab.com/Linaro/lkft/mirrors/stable/linux-stable-rc
* git branch: linux-5.15.y
* git commit: 46b26da4b8729ab6a0bd90326cf182a2535d938e
* git describe: v5.15.129-10-g46b26da4b872
* test details:
https://qa-reports.linaro.org/lkft/linux-stable-rc-linux-5.15.y/build/v5.15.129-10-g46b26da4b872

## Test Regressions (compared to v5.15.129)

## Metric Regressions (compared to v5.15.129)

## Test Fixes (compared to v5.15.129)

## Metric Fixes (compared to v5.15.129)

## Test result summary
total: 98073, pass: 79708, fail: 2412, skip: 15861, xfail: 92

## Build Summary
* arc: 5 total, 5 passed, 0 failed
* arm: 114 total, 113 passed, 1 failed
* arm64: 43 total, 42 passed, 1 failed
* i386: 34 total, 33 passed, 1 failed
* mips: 27 total, 26 passed, 1 failed
* parisc: 4 total, 4 passed, 0 failed
* powerpc: 26 total, 25 passed, 1 failed
* riscv: 11 total, 10 passed, 1 failed
* s390: 12 total, 11 passed, 1 failed
* sh: 14 total, 12 passed, 2 failed
* sparc: 8 total, 8 passed, 0 failed
* x86_64: 37 total, 36 passed, 1 failed

## Test suites summary
* boot
* kselftest-android
* kselftest-arm64
* kselftest-breakpoints
* kselftest-capabilities
* kselftest-cgroup
* kselftest-clone3
* kselftest-core
* kselftest-cpu-hotplug
* kselftest-cpufreq
* kselftest-drivers-dma-buf
* kselftest-efivarfs
* kselftest-exec
* kselftest-filesystems
* kselftest-filesystems-binderfs
* kselftest-filesystems-epoll
* kselftest-firmware
* kselftest-fpu
* kselftest-ftrace
* kselftest-futex
* kselftest-gpio
* kselftest-intel_pstate
* kselftest-ipc
* kselftest-ir
* kselftest-kcmp
* kselftest-kexec
* kselftest-kvm
* kselftest-lib
* kselftest-membarrier
* kselftest-memfd
* kselftest-memory-hotplug
* kselftest-mincore
* kselftest-mount
* kselftest-mqueue
* kselftest-net
* kselftest-net-forwarding
* kselftest-net-mptcp
* kselftest-netfilter
* kselftest-nsfs
* kselftest-openat2
* kselftest-pid_namespace
* kselftest-pidfd
* kselftest-proc
* kselftest-pstore
* kselftest-ptrace
* kselftest-rseq
* kselftest-rtc
* kselftest-seccomp
* kselftest-sigaltstack
* kselftest-size
* kselftest-splice
* kselftest-static_keys
* kselftest-sync
* kselftest-sysctl
* kselftest-tc-testing
* kselftest-timens
* kselftest-timers
* kselftest-tmpfs
* kselftest-tpm2
* kselftest-user
* kselftest-user_events
* kselftest-vDSO
* kselftest-vm
* kselftest-watchdog
* kselftest-x86
* kselftest-zram
* kunit
* kvm-unit-tests
* libgpiod
* log-parser-boot
* log-parser-test
* ltp-cap_bounds
* ltp-commands
* ltp-containers
* ltp-controllers
* ltp-cpuhotplug
* ltp-crypto
* ltp-cve
* ltp-dio
* ltp-fcntl-locktests
* ltp-filecaps
* ltp-fs
* ltp-fs_bind
* ltp-fs_perms_simple
* ltp-fsx
* ltp-hugetlb
* ltp-io
* ltp-ipc
* ltp-math
* ltp-mm
* ltp-nptl
* ltp-pty
* ltp-sched
* ltp-securebits
* ltp-smoke
* ltp-syscalls
* ltp-tracing
* network-basic-tests
* perf
* rcutorture
* v4l2-compliance

--
Linaro LKFT
https://lkft.linaro.org

Re: [PATCH 5.15 0/9] 5.15.130-rc1 review

[Shuah Khan]

On 8/31/23 05:10, Greg Kroah-Hartman wrote:
> This is the start of the stable review cycle for the 5.15.130 release.
> There are 9 patches in this series, all will be posted as a response
> to this one.  If anyone has any issues with these being applied, please
> let me know.
> 
> Responses should be made by Sat, 02 Sep 2023 11:08:22 +0000.
> Anything received after that time might be too late.
> 
> The whole patch series can be found in one patch at:
> 	https://www.kernel.org/pub/linux/kernel/v5.x/stable-review/patch-5.15.130-rc1.gz
> or in the git tree and branch at:
> 	git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable-rc.git linux-5.15.y
> and the diffstat can be found below.
> 
> thanks,
> 
> greg k-h
> 

Compiled and booted on my test system. No dmesg regressions.

Tested-by: Shuah Khan <skhan@linuxfoundation.org>

thanks,
-- Shuah

Re: [PATCH 5.15 0/9] 5.15.130-rc1 review

[Jon Hunter]

On Thu, 31 Aug 2023 13:10:08 +0200, Greg Kroah-Hartman wrote:
> This is the start of the stable review cycle for the 5.15.130 release.
> There are 9 patches in this series, all will be posted as a response
> to this one.  If anyone has any issues with these being applied, please
> let me know.
> 
> Responses should be made by Sat, 02 Sep 2023 11:08:22 +0000.
> Anything received after that time might be too late.
> 
> The whole patch series can be found in one patch at:
> 	https://www.kernel.org/pub/linux/kernel/v5.x/stable-review/patch-5.15.130-rc1.gz
> or in the git tree and branch at:
> 	git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable-rc.git linux-5.15.y
> and the diffstat can be found below.
> 
> thanks,
> 
> greg k-h

All tests passing for Tegra ...

Test results for stable-v5.15:
    11 builds:	11 pass, 0 fail
    28 boots:	28 pass, 0 fail
    114 tests:	114 pass, 0 fail

Linux version:	5.15.130-rc1-g46b26da4b872
Boards tested:	tegra124-jetson-tk1, tegra186-p2771-0000,
                tegra194-p2972-0000, tegra194-p3509-0000+p3668-0000,
                tegra20-ventana, tegra210-p2371-2180,
                tegra210-p3450-0000, tegra30-cardhu-a04

Tested-by: Jon Hunter <jonathanh@nvidia.com>

Jon

Re: [PATCH 5.15 0/9] 5.15.130-rc1 review

[Guenter Roeck]

On Thu, Aug 31, 2023 at 01:10:08PM +0200, Greg Kroah-Hartman wrote:
> This is the start of the stable review cycle for the 5.15.130 release.
> There are 9 patches in this series, all will be posted as a response
> to this one.  If anyone has any issues with these being applied, please
> let me know.
> 
> Responses should be made by Sat, 02 Sep 2023 11:08:22 +0000.
> Anything received after that time might be too late.
> 

Build results:
	total: 155 pass: 155 fail: 0
Qemu test results:
	total: 501 pass: 501 fail: 0

Tested-by: Guenter Roeck <linux@roeck-us.net>

Guenter