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When we dynamically generate a name for a configuration in get-reg-list
we use strcat() to append to a buffer allocated using malloc() but we
never initialise that buffer. Since malloc() offers no guarantees
regarding the contents of the memory it returns this can lead to us
corrupting, and likely overflowing, the buffer:
vregs: PASS
vregs+pmu: PASS
sve: PASS
sve+pmu: PASS
vregs+pauth_address+pauth_generic: PASS
X?vr+gspauth_addre+spauth_generi+pmu: PASS
The bug is that strcat() should have been strcpy(), and that replacement
would be enough to fix it, but there are other things in the function
that leave something to be desired. In particular, an (incorrectly)
empty config would cause an out of bounds access to c->name[-1].
Since the strcpy() call relies on c->name[0..len-1] being initialized,
enforce that invariant throughout the function.
Fixes: 2f9ace5d4557 ("KVM: arm64: selftests: get-reg-list: Introduce vcpu configs")
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Co-developed-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Mark Brown <broonie@kernel.org>
Message-Id: <20231211-kvm-get-reg-list-str-init-v3-1-6554c71c77b1@kernel.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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The init_irq_stacks() has been changed to use the correct node:
https://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git/commit/?id=75b5e0bf90bf
The init_irq_scs() has the same issue with init_irq_stacks():
cpu_to_node() is not initialized yet, it does not work.
This patch uses early_cpu_to_node() to set the init_irq_scs()
with the correct node.
Signed-off-by: Huang Shijie <shijie@os.amperecomputing.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Link: https://lore.kernel.org/r/20231213012046.12014-1-shijie@os.amperecomputing.com
Signed-off-by: Will Deacon <will@kernel.org>
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Aneesh and Naveen are helping out with some aspects of upstream
maintenance, add them as reviewers.
Acked-by: "Aneesh Kumar K.V (IBM)" <aneesh.kumar@kernel.org>
Acked-by: "Naveen N. Rao" <naveen.n.rao@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20231205051105.736470-1-mpe@ellerman.id.au
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CPU features can be determined in makedumpfile, using
'cur_cpu_spec.cpu_features'.
This provides more data to makedumpfile about the crashed system, and
can help in filtering the vmcore accordingly.
Signed-off-by: Aditya Gupta <adityag@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20230920105706.853626-2-adityag@linux.ibm.com
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kasprintf() returns a pointer to dynamically allocated memory
which can be NULL upon failure.
Fixes: 885dcd709ba9 ("powerpc/perf: Add nest IMC PMU support")
Signed-off-by: Kunwu Chan <chentao@kylinos.cn>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20231126093719.1440305-1-chentao@kylinos.cn
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kasprintf() returns a pointer to dynamically allocated memory
which can be NULL upon failure.
Fixes: b9ef7b4b867f ("powerpc: Convert to using %pOFn instead of device_node.name")
Signed-off-by: Kunwu Chan <chentao@kylinos.cn>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20231126095739.1501990-1-chentao@kylinos.cn
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kasprintf() returns a pointer to dynamically allocated memory
which can be NULL upon failure.
Fixes: 2717a33d6074 ("powerpc/opal-irqchip: Use interrupt names if present")
Signed-off-by: Kunwu Chan <chentao@kylinos.cn>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20231127030755.1546750-1-chentao@kylinos.cn
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kasprintf() returns a pointer to dynamically allocated memory
which can be NULL upon failure.
Add a null pointer check, and release 'ent' to avoid memory leaks.
Fixes: bfd2f0d49aef ("powerpc/powernv: Get rid of old scom_controller abstraction")
Signed-off-by: Kunwu Chan <chentao@kylinos.cn>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20231208085937.107210-1-chentao@kylinos.cn
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kasprintf() returns a pointer to dynamically allocated memory
which can be NULL upon failure. Ensure the allocation was successful
by checking the pointer validity.
Suggested-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Suggested-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Kunwu Chan <chentao@kylinos.cn>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20231204023223.2447523-1-chentao@kylinos.cn
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The hypervisor returns migration failure if all VAS windows are not
closed. During pre-migration stage, vas_migration_handler() sets
migration_in_progress flag and closes all windows from the list.
The allocate VAS window routine checks the migration flag, setup
the window and then add it to the list. So there is possibility of
the migration handler missing the window that is still in the
process of setup.
t1: Allocate and open VAS t2: Migration event
window
lock vas_pseries_mutex
If migration_in_progress set
unlock vas_pseries_mutex
return
open window HCALL
unlock vas_pseries_mutex
Modify window HCALL lock vas_pseries_mutex
setup window migration_in_progress=true
Closes all windows from the list
// May miss windows that are
// not in the list
unlock vas_pseries_mutex
lock vas_pseries_mutex return
if nr_closed_windows == 0
// No DLPAR CPU or migration
add window to the list
// Window will be added to the
// list after the setup is completed
unlock vas_pseries_mutex
return
unlock vas_pseries_mutex
Close VAS window
// due to DLPAR CPU or migration
return -EBUSY
This patch resolves the issue with the following steps:
- Set the migration_in_progress flag without holding mutex.
- Introduce nr_open_wins_progress counter in VAS capabilities
struct
- This counter tracks the number of open windows are still in
progress
- The allocate setup window thread closes windows if the migration
is set and decrements nr_open_window_progress counter
- The migration handler waits for no in-progress open windows.
The code flow with the fix is as follows:
t1: Allocate and open VAS t2: Migration event
window
lock vas_pseries_mutex
If migration_in_progress set
unlock vas_pseries_mutex
return
open window HCALL
nr_open_wins_progress++
// Window opened, but not
// added to the list yet
unlock vas_pseries_mutex
Modify window HCALL migration_in_progress=true
setup window lock vas_pseries_mutex
Closes all windows from the list
While nr_open_wins_progress {
unlock vas_pseries_mutex
lock vas_pseries_mutex sleep
if nr_closed_windows == 0 // Wait if any open window in
or migration is not started // progress. The open window
// No DLPAR CPU or migration // thread closes the window without
add window to the list // adding to the list and return if
nr_open_wins_progress-- // the migration is in progress.
unlock vas_pseries_mutex
return
Close VAS window
nr_open_wins_progress--
unlock vas_pseries_mutex
return -EBUSY lock vas_pseries_mutex
}
unlock vas_pseries_mutex
return
Fixes: 37e6764895ef ("powerpc/pseries/vas: Add VAS migration handler")
Signed-off-by: Haren Myneni <haren@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20231125235104.3405008-1-haren@linux.ibm.com
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Yanteng Si says:
====================
stmmac: Some bug fixes
* Put Krzysztof's patch into my thread, pick Conor's Reviewed-by
tag and Jiaxun's Acked-by tag.(prev version is RFC patch)
* I fixed an Oops related to mdio, mainly to ensure that
mdio is initialized before use, because it will be used
in a series of patches I am working on.
see <https://lore.kernel.org/loongarch/cover.1699533745.git.siyanteng@loongson.cn/T/#t>
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
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Device binds to proper PCI ID (LOONGSON, 0x7a03), already listed in DTS,
so checking for some other compatible does not make sense. It cannot be
bound to unsupported platform.
Drop useless, incorrect (space in between) and undocumented compatible.
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Yanteng Si <siyanteng@loongson.cn>
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Acked-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Device binds to proper PCI ID (LOONGSON, 0x7a03), already listed in DTS,
so checking for some other compatible does not make sense. It cannot be
bound to unsupported platform.
Drop useless, incorrect (space in between) and undocumented compatible.
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Yanteng Si <siyanteng@loongson.cn>
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Acked-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Generic code will use mdio. If it is not initialized before use,
the kernel will Oops.
Fixes: 30bba69d7db4 ("stmmac: pci: Add dwmac support for Loongson")
Signed-off-by: Yanteng Si <siyanteng@loongson.cn>
Signed-off-by: Feiyang Chen <chenfeiyang@loongson.cn>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Originally was in the panel-simple, but belongs to panel-simple-dsi.
See arch/arm/boot/dts/nvidia/tegra114-roth.dts for more details.
Resolves the following warning:
```
arch/arm/boot/dts/tegra114-roth.dt.yaml: panel@0: 'reg' does not match any of the regexes: 'pinctrl-[0-9]+'
From schema: Documentation/devicetree/bindings/display/panel/panel-simple.yaml
```
Fixes: 310abcea76e9 ("dt-bindings: display: convert simple lg panels to DT Schema")
Signed-off-by: David Heidelberg <david@ixit.cz>
Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Acked-by: Jessica Zhang <quic_jesszhan@quicinc.com>
Link: https://lore.kernel.org/r/20231212200934.99262-1-david@ixit.cz
Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20231212200934.99262-1-david@ixit.cz
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Commit d49a0626216b95 ("arch: Introduce CONFIG_FUNCTION_ALIGNMENT")
introduced a generic function-alignment infrastructure. Move to using
FUNCTION_ALIGNMENT_4B on powerpc, to use the same alignment as that of
the existing _GLOBAL macro.
Signed-off-by: Sathvika Vasireddy <sv@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/21892186ec44abe24df0daf64f577dac0e78783f.1702045299.git.naveen@kernel.org
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ftrace_stub is within the same CU, so there is no need for a subsequent
nop instruction.
Signed-off-by: Naveen N Rao <naveen@kernel.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/8ee5ec520e37d5523654bb2cd65a17512fb774e2.1702045299.git.naveen@kernel.org
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Replace seven spaces with a tab character to fix an indentation issue
reported by the kernel test robot.
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202311221731.alUwTDIm-lkp@intel.com/
Signed-off-by: Naveen N Rao <naveen@kernel.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/9f058227bd9243f0842786ef7228d87ab10d29f6.1702045299.git.naveen@kernel.org
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Consistently testing system parameter access is a bit difficult by
nature -- the set of parameters available depends on the model and
system configuration, and updating a parameter should be considered a
destructive operation reserved for the admin.
So we validate some of the error paths and retrieve the SPLPAR
characteristics string, but not much else.
Signed-off-by: Nathan Lynch <nathanl@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20231212-papr-sys_rtas-vs-lockdown-v6-13-e9eafd0c8c6c@linux.ibm.com
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Add selftests for /dev/papr-vpd, exercising the common expected use
cases:
* Retrieve all VPD by passing an empty location code.
* Retrieve the "system VPD" by passing a location code derived from DT
root node properties, as done by the vpdupdate command.
The tests also verify that certain intended properties of the driver
hold:
* Passing an unterminated location code to PAPR_VPD_CREATE_HANDLE gets
EINVAL.
* Passing a NULL location code pointer to PAPR_VPD_CREATE_HANDLE gets
EFAULT.
* Closing the device node without first issuing a
PAPR_VPD_CREATE_HANDLE command to it succeeds.
* Releasing a handle without first consuming any data from it
succeeds.
* Re-reading the contents of a handle returns the same data as the
first time.
Some minimal validation of the returned data is performed.
The tests are skipped on systems where the papr-vpd driver does not
initialize, making this useful only on PowerVM LPARs at this point.
Signed-off-by: Nathan Lynch <nathanl@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20231212-papr-sys_rtas-vs-lockdown-v6-12-e9eafd0c8c6c@linux.ibm.com
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Until now the papr_sysparm APIs have been kernel-internal. But user
space needs access to PAPR system parameters too. The only method
available to user space today to get or set system parameters is using
sys_rtas() and /dev/mem to pass RTAS-addressable buffers between user
space and firmware. This is incompatible with lockdown and should be
deprecated.
So provide an alternative ABI to user space in the form of a
/dev/papr-sysparm character device with just two ioctl commands (get
and set). The data payloads involved are small enough to fit in the
ioctl argument buffer, making the code relatively simple.
Exposing the system parameters through sysfs has been considered but
it would be too awkward:
* The kernel currently does not have to contain an exhaustive list of
defined system parameters. This is a convenient property to maintain
because we don't have to update the kernel whenever a new parameter
is added to PAPR. Exporting a named attribute in sysfs for each
parameter would negate this.
* Some system parameters are text-based and some are not.
* Retrieval of at least one system parameter requires input data,
which a simple read-oriented interface can't support.
Signed-off-by: Nathan Lynch <nathanl@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20231212-papr-sys_rtas-vs-lockdown-v6-11-e9eafd0c8c6c@linux.ibm.com
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The ability to get and set system parameters will be exposed to user
space, so let's get a little more strict about malformed
papr_sysparm_buf objects.
* Create accessors for the length field of struct papr_sysparm_buf.
The length is always stored in MSB order and this is better than
spreading the necessary conversions all over.
* Reject attempts to submit invalid buffers to RTAS.
* Warn if RTAS returns a buffer with an invalid length, clamping the
returned length to a safe value that won't overrun the buffer.
These are meant as precautionary measures to mitigate both firmware
and kernel bugs in this area, should they arise, but I am not aware of
any.
Signed-off-by: Nathan Lynch <nathanl@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20231212-papr-sys_rtas-vs-lockdown-v6-10-e9eafd0c8c6c@linux.ibm.com
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PowerVM LPARs may retrieve Vital Product Data (VPD) for system
components using the ibm,get-vpd RTAS function.
We can expose this to user space with a /dev/papr-vpd character
device, where the programming model is:
struct papr_location_code plc = { .str = "", }; /* obtain all VPD */
int devfd = open("/dev/papr-vpd", O_RDONLY);
int vpdfd = ioctl(devfd, PAPR_VPD_CREATE_HANDLE, &plc);
size_t size = lseek(vpdfd, 0, SEEK_END);
char *buf = malloc(size);
pread(devfd, buf, size, 0);
When a file descriptor is obtained from ioctl(PAPR_VPD_CREATE_HANDLE),
the file contains the result of a complete ibm,get-vpd sequence. The
file contents are immutable from the POV of user space. To get a new
view of the VPD, the client must create a new handle.
This design choice insulates user space from most of the complexities
that ibm,get-vpd brings:
* ibm,get-vpd must be called more than once to obtain complete
results.
* Only one ibm,get-vpd call sequence should be in progress at a time;
interleaved sequences will disrupt each other. Callers must have a
protocol for serializing their use of the function.
* A call sequence in progress may receive a "VPD changed, try again"
status, requiring the client to abandon the sequence and start
over.
The memory required for the VPD buffers seems acceptable, around 20KB
for all VPD on one of my systems. And the value of the
/rtas/ibm,vpd-size DT property (the estimated maximum size of VPD) is
consistently 300KB across various systems I've checked.
I've implemented support for this new ABI in the rtas_get_vpd()
function in librtas, which the vpdupdate command currently uses to
populate its VPD database. I've verified that an unmodified vpdupdate
binary generates an identical database when using a librtas.so that
prefers the new ABI.
Along with the papr-vpd.h header exposed to user space, this
introduces a common papr-miscdev.h uapi header to share a base ioctl
ID with similar drivers to come.
Tested-by: Michal Suchánek <msuchanek@suse.de>
Signed-off-by: Nathan Lynch <nathanl@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20231212-papr-sys_rtas-vs-lockdown-v6-9-e9eafd0c8c6c@linux.ibm.com
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If the function descriptor has a populated lock member, then callers
are required to hold it across calls. Now that the firmware activation
sequence is appropriately guarded, we can warn when the requirement
isn't satisfied.
__do_enter_rtas_trace() gets reorganized a bit as a result of
performing the function descriptor lookup unconditionally now.
Reviewed-by: "Aneesh Kumar K.V (IBM)" <aneesh.kumar@kernel.org>
Signed-off-by: Nathan Lynch <nathanl@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20231212-papr-sys_rtas-vs-lockdown-v6-8-e9eafd0c8c6c@linux.ibm.com
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Use rtas_ibm_activate_firmware_lock to prevent interleaving call
sequences of the ibm,activate-firmware RTAS function, which typically
requires multiple calls to complete the update. While the spec does
not specifically prohibit interleaved sequences, there's almost
certainly no advantage to allowing them.
Reviewed-by: "Aneesh Kumar K.V (IBM)" <aneesh.kumar@kernel.org>
Signed-off-by: Nathan Lynch <nathanl@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20231212-papr-sys_rtas-vs-lockdown-v6-7-e9eafd0c8c6c@linux.ibm.com
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On RTAS platforms there is a general restriction that the OS must not
enter RTAS on more than one CPU at a time. This low-level
serialization requirement is satisfied by holding a spin
lock (rtas_lock) across most RTAS function invocations.
However, some pseries RTAS functions require multiple successive calls
to complete a logical operation. Beginning a new call sequence for such a
function may disrupt any other sequences of that function already in
progress. Safe and reliable use of these functions effectively
requires higher-level serialization beyond what is already done at the
level of RTAS entry and exit.
Where a sequence-based RTAS function is invoked only through
sys_rtas(), with no in-kernel users, there is no issue as far as the
kernel is concerned. User space is responsible for appropriately
serializing its call sequences. (Whether user space code actually
takes measures to prevent sequence interleaving is another matter.)
Examples of such functions currently include ibm,platform-dump and
ibm,get-vpd.
But where a sequence-based RTAS function has both user space and
in-kernel uesrs, there is a hazard. Even if the in-kernel call sites
of such a function serialize their sequences correctly, a user of
sys_rtas() can invoke the same function at any time, potentially
disrupting a sequence in progress.
So in order to prevent disruption of kernel-based RTAS call sequences,
they must serialize not only with themselves but also with sys_rtas()
users, somehow. Preferably without adding more function-specific hacks
to sys_rtas(). This is a prerequisite for adding an in-kernel call
sequence of ibm,get-vpd, which is in a change to follow.
Note that it has never been feasible for the kernel to prevent
sys_rtas()-based sequences from being disrupted because control
returns to user space on every call. sys_rtas()-based users of these
functions have always been, and continue to be, responsible for
coordinating their call sequences with other users, even those which
may invoke the RTAS functions through less direct means than
sys_rtas(). This is an unavoidable consequence of exposing
sequence-based RTAS functions through sys_rtas().
* Add an optional mutex member to struct rtas_function.
* Statically define a mutex for each RTAS function with known call
sequence serialization requirements, and assign its address to the
.lock member of the corresponding function table entry, along with
justifying commentary.
* In sys_rtas(), if the table entry for the RTAS function being
called has a populated lock member, acquire it before taking
rtas_lock and entering RTAS.
* Kernel-based RTAS call sequences are expected to access the
appropriate mutex explicitly by name. For example, a user of the
ibm,activate-firmware RTAS function would do:
int token = rtas_function_token(RTAS_FN_IBM_ACTIVATE_FIRMWARE);
int fwrc;
mutex_lock(&rtas_ibm_activate_firmware_lock);
do {
fwrc = rtas_call(token, 0, 1, NULL);
} while (rtas_busy_delay(fwrc));
mutex_unlock(&rtas_ibm_activate_firmware_lock);
There should be no perceivable change introduced here except that
concurrent callers of the same RTAS function via sys_rtas() may block
on a mutex instead of spinning on rtas_lock.
Signed-off-by: Nathan Lynch <nathanl@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20231212-papr-sys_rtas-vs-lockdown-v6-6-e9eafd0c8c6c@linux.ibm.com
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The rtas system call handler sys_rtas() delegates certain input
validation steps to a helper function: block_rtas_call(). One of these
steps ensures that the user-supplied token value maps to a known RTAS
function. This is done by performing a "reverse" token-to-function
lookup via rtas_token_to_function_untrusted() to obtain an
rtas_function object.
In changes to come, sys_rtas() itself will need the function
descriptor for the token. To prepare:
* Move the lookup and validation up into sys_rtas() and pass the
resulting rtas_function pointer to block_rtas_call(), which is
otherwise unconcerned with the token value.
* Change block_rtas_call() to report the RTAS function name instead of
the token value on validation failures, since it can now rely on
having a valid function descriptor.
One behavior change is that sys_rtas() now silently errors out when
passed a bad token, before calling block_rtas_call(). So we will no
longer log "RTAS call blocked - exploit attempt?" on invalid
tokens. This is consistent with how sys_rtas() currently handles other
"metadata" (nargs and nret), while block_rtas_call() is primarily
concerned with validating the arguments to be passed to specific RTAS
functions.
Signed-off-by: Nathan Lynch <nathanl@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20231212-papr-sys_rtas-vs-lockdown-v6-5-e9eafd0c8c6c@linux.ibm.com
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Not all of the generic RTAS function statuses specified in PAPR have
symbolic constants and descriptions in rtas.h. Fix this, providing a
little more background, slightly updating the existing wording, and
improving the formatting.
Reviewed-by: "Aneesh Kumar K.V (IBM)" <aneesh.kumar@kernel.org>
Signed-off-by: Nathan Lynch <nathanl@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20231212-papr-sys_rtas-vs-lockdown-v6-4-e9eafd0c8c6c@linux.ibm.com
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Enabling any of the powerpc:rtas_* tracepoints at boot is likely to
result in an oops on RTAS platforms. For example, booting a QEMU
pseries model with 'trace_event=powerpc:rtas_input' in the command
line leads to:
BUG: Kernel NULL pointer dereference on read at 0x00000008
Oops: Kernel access of bad area, sig: 7 [#1]
NIP [c00000000004231c] do_enter_rtas+0x1bc/0x460
LR [c00000000004231c] do_enter_rtas+0x1bc/0x460
Call Trace:
do_enter_rtas+0x1bc/0x460 (unreliable)
rtas_call+0x22c/0x4a0
rtas_get_boot_time+0x80/0x14c
read_persistent_clock64+0x124/0x150
read_persistent_wall_and_boot_offset+0x28/0x58
timekeeping_init+0x70/0x348
start_kernel+0xa0c/0xc1c
start_here_common+0x1c/0x20
(This is preceded by a warning for the failed lookup in
rtas_token_to_function().)
This happens when __do_enter_rtas_trace() attempts a token to function
descriptor lookup before the xarray containing the mappings has been
set up.
Fall back to linear scan of the table if rtas_token_to_function_xarray
is empty.
Fixes: 24098f580e2b ("powerpc/rtas: add tracepoints around RTAS entry")
Reviewed-by: "Aneesh Kumar K.V (IBM)" <aneesh.kumar@kernel.org>
Signed-off-by: Nathan Lynch <nathanl@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20231212-papr-sys_rtas-vs-lockdown-v6-3-e9eafd0c8c6c@linux.ibm.com
|
|
Add a convenience macro for iterating over every element of the
internal function table and convert the one site that can use it. An
additional user of the macro is anticipated in changes to follow.
Reviewed-by: "Aneesh Kumar K.V (IBM)" <aneesh.kumar@kernel.org>
Signed-off-by: Nathan Lynch <nathanl@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20231212-papr-sys_rtas-vs-lockdown-v6-2-e9eafd0c8c6c@linux.ibm.com
|
|
rtas_token_to_function() WARNs when passed an invalid token; it's
meant to catch bugs in kernel-based users of RTAS functions. However,
user space controls the token value passed to rtas_token_to_function()
by block_rtas_call(), so user space with sufficient privilege to use
sys_rtas() can trigger the warnings at will:
unexpected failed lookup for token 2048
WARNING: CPU: 20 PID: 2247 at arch/powerpc/kernel/rtas.c:556
rtas_token_to_function+0xfc/0x110
...
NIP rtas_token_to_function+0xfc/0x110
LR rtas_token_to_function+0xf8/0x110
Call Trace:
rtas_token_to_function+0xf8/0x110 (unreliable)
sys_rtas+0x188/0x880
system_call_exception+0x268/0x530
system_call_common+0x160/0x2c4
It's desirable to continue warning on bogus tokens in
rtas_token_to_function(). Currently it is used to look up RTAS
function descriptors when tracing, where we know there has to have
been a successful descriptor lookup by different means already, and it
would be a serious inconsistency for the reverse lookup to fail.
So instead of weakening rtas_token_to_function()'s contract by
removing the warnings, introduce rtas_token_to_function_untrusted(),
which has no opinion on failed lookups. Convert block_rtas_call() and
rtas_token_to_function() to use it.
Fixes: 8252b88294d2 ("powerpc/rtas: improve function information lookups")
Signed-off-by: Nathan Lynch <nathanl@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20231212-papr-sys_rtas-vs-lockdown-v6-1-e9eafd0c8c6c@linux.ibm.com
|
|
Based on the tcp man page, if TCP_NODELAY is set, it disables Nagle's algorithm
and packets are sent as soon as possible. However in the `tcp_push` function
where autocorking is evaluated the `nonagle` value set by TCP_NODELAY is not
considered which can trigger unexpected corking of packets and induce delays.
For example, if two packets are generated as part of a server's reply, if the
first one is not transmitted on the wire quickly enough, the second packet can
trigger the autocorking in `tcp_push` and be delayed instead of sent as soon as
possible. It will either wait for additional packets to be coalesced or an ACK
from the client before transmitting the corked packet. This can interact badly
if the receiver has tcp delayed acks enabled, introducing 40ms extra delay in
completion times. It is not always possible to control who has delayed acks
set, but it is possible to adjust when and how autocorking is triggered.
Patch prevents autocorking if the TCP_NODELAY flag is set on the socket.
Patch has been tested using an AWS c7g.2xlarge instance with Ubuntu 22.04 and
Apache Tomcat 9.0.83 running the basic servlet below:
import java.io.IOException;
import java.io.OutputStreamWriter;
import java.io.PrintWriter;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
public class HelloWorldServlet extends HttpServlet {
@Override
protected void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
response.setContentType("text/html;charset=utf-8");
OutputStreamWriter osw = new OutputStreamWriter(response.getOutputStream(),"UTF-8");
String s = "a".repeat(3096);
osw.write(s,0,s.length());
osw.flush();
}
}
Load was applied using wrk2 (https://github.com/kinvolk/wrk2) from an AWS
c6i.8xlarge instance. With the current auto-corking behavior and TCP_NODELAY
set an additional 40ms latency from P99.99+ values are observed. With the
patch applied we see no occurrences of 40ms latencies. The patch has also been
tested with iperf and uperf benchmarks and no regression was observed.
# No patch with tcp_autocorking=1 and TCP_NODELAY set on all sockets
./wrk -t32 -c128 -d40s --latency -R10000 http://172.31.49.177:8080/hello/hello'
...
50.000% 0.91ms
75.000% 1.12ms
90.000% 1.46ms
99.000% 1.73ms
99.900% 1.96ms
99.990% 43.62ms <<< 40+ ms extra latency
99.999% 48.32ms
100.000% 49.34ms
# With patch
./wrk -t32 -c128 -d40s --latency -R10000 http://172.31.49.177:8080/hello/hello'
...
50.000% 0.89ms
75.000% 1.13ms
90.000% 1.44ms
99.000% 1.67ms
99.900% 1.78ms
99.990% 2.27ms <<< no 40+ ms extra latency
99.999% 3.71ms
100.000% 4.57ms
Fixes: f54b311142a9 ("tcp: auto corking")
Signed-off-by: Salvatore Dipietro <dipiets@amazon.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
|
|
affinity_domain_via_partition_show function
To access hv-gpci kernel interface files data, the
"Enable Performance Information Collection" option has to be set
in hmc. Incase that option is not set and user try to read
the interface files, it should give error message as
operation not permitted.
Result of accessing added interface files with disabled
performance collection option:
[command]# cat processor_bus_topology
cat: processor_bus_topology: Operation not permitted
[command]# cat processor_config
cat: processor_config: Operation not permitted
[command]# cat affinity_domain_via_domain
cat: affinity_domain_via_domain: Operation not permitted
[command]# cat affinity_domain_via_virtual_processor
cat: affinity_domain_via_virtual_processor: Operation not permitted
[command]# cat affinity_domain_via_partition
Based on above result there is no error message when reading
affinity_domain_via_partition file because of missing
check for failed hcall. Fix this issue by adding
a check in the start of affinity_domain_via_partition_show
function, to return error incase hcall fails, with error type
other then H_PARAMETER.
Fixes: a15e0d6a6929 ("powerpc/hv_gpci: Add sysfs file inside hv_gpci device to show affinity domain via partition information")
Reported-by: Disha Goel <disgoel@linux.vnet.ibm.com>
Signed-off-by: Kajol Jain <kjain@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20231116122033.160964-1-kjain@linux.ibm.com
|
|
This reverts commit a5f4ca68f348ac059efd6a3d7ad4040aed1c0818.
Pulling in the Arm-specific 'linux/perf/arm_pmu.h' header breaks the
allmodconfig build for x86:
> In file included from drivers/perf/arm_dmc620_pmu.c:26:
> include/linux/perf/arm_pmu.h:15:10: fatal error: asm/cputype.h: No such file or directory
> 15 | #include <asm/cputype.h>
> | ^~~~~~~~~~~~~~~
Just put things back like they were so that the driver can continue to
be compile-tested on a variety of architectures.
Link: https://lore.kernel.org/r/20231213100931.12d9d85e@canb.auug.org.au
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Will Deacon <will@kernel.org>
|
|
https://git.kernel.org/pub/scm/linux/kernel/git/chunkuang.hu/linux into drm-fixes
Mediatek DRM Fixes - 20231211
1. mtk_disp_gamma: Fix breakage due to merge issue
2. fix kernel oops if no crtc is found
3. Add spinlock for setting vblank event in atomic_begin
4. Fix access violation in mtk_drm_crtc_dma_dev_get
Signed-off-by: Dave Airlie <airlied@redhat.com>
From: Chun-Kuang Hu <chunkuang.hu@kernel.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20231211151510.6749-1-chunkuang.hu@kernel.org
|
|
With subtle timings changes, we can now sometimes get an external abort on
non-linefetch error booting am3 devices at sysc_reset(). This is because
of a missing reset delay needed for the usb target module.
Looks like we never enabled the delay earlier for am3, although a similar
issue was seen earlier with a similar usb setup for dm814x as described in
commit ebf244148092 ("ARM: OMAP2+: Use srst_udelay for USB on dm814x").
Cc: stable@vger.kernel.org
Fixes: 0782e8572ce4 ("ARM: dts: Probe am335x musb with ti-sysc")
Signed-off-by: Tony Lindgren <tony@atomide.com>
|
|
The emulated IMSIC update the external interrupt pending depending on
the value of eidelivery and topei. It might lose an interrupt when it
is interrupted before setting the new value to the pending status.
For example, when VCPU0 sends an IPI to VCPU1 via IMSIC:
VCPU0 VCPU1
CSRSWAP topei = 0
The VCPU1 has claimed all the external
interrupt in its interrupt handler.
topei of VCPU1's IMSIC = 0
set pending in VCPU1's IMSIC
topei of VCPU1' IMSIC = 1
set the external interrupt
pending of VCPU1
clear the external interrupt pending
of VCPU1
When the VCPU1 switches back to VS mode, it exits the interrupt handler
because the result of CSRSWAP topei is 0. If there are no other external
interrupts injected into the VCPU1's IMSIC, VCPU1 will never know this
pending interrupt unless it initiative read the topei.
If the interruption occurs between updating interrupt pending in IMSIC
and updating external interrupt pending of VCPU, it will not cause a
problem. Suppose that the VCPU1 clears the IPI pending in IMSIC right
after VCPU0 sets the pending, the external interrupt pending of VCPU1
will not be set because the topei is 0. But when the VCPU1 goes back to
VS mode, the pending IPI will be reported by the CSRSWAP topei, it will
not lose this interrupt.
So we only need to make the external interrupt updating procedure as a
critical section to avoid the problem.
Fixes: db8b7e97d613 ("RISC-V: KVM: Add in-kernel virtualization of AIA IMSIC")
Tested-by: Roy Lin <roy.lin@sifive.com>
Tested-by: Wayling Chen <wayling.chen@sifive.com>
Co-developed-by: Vincent Chen <vincent.chen@sifive.com>
Signed-off-by: Vincent Chen <vincent.chen@sifive.com>
Signed-off-by: Yong-Xuan Wang <yongxuan.wang@sifive.com>
Signed-off-by: Anup Patel <anup@brainfault.org>
|
|
print_reg() will print everything it knows when it encounters
a register ID it's unfamiliar with in the default cases of its
decoding switches. Fix several issues with these (until now,
never tested) paths; missing newlines in printfs, missing
complement operator in mask, and missing return in order to
avoid continuing to decode.
Fixes: 62d0c458f828 ("KVM: riscv: selftests: get-reg-list print_reg should never fail")
Signed-off-by: Andrew Jones <ajones@ventanamicro.com>
Reviewed-by: Haibo Xu <haibo1.xu@intel.com>
Signed-off-by: Anup Patel <anup@brainfault.org>
|
|
Add the VID and PID of Razer Wolverine V2 to xpad_device.
Signed-off-by: Luca Weiss <luca@z3ntu.xyz>
Link: https://lore.kernel.org/r/20231125-razer-wolverine-v2-v1-1-979fe9f9288e@z3ntu.xyz
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
|
|
If for some reason the trace_marker write does not have a nul byte for the
string, it will overflow the print:
trace_seq_printf(s, ": %s", field->buf);
The field->buf could be missing the nul byte. To prevent overflow, add the
max size that the buf can be by using the event size and the field
location.
int max = iter->ent_size - offsetof(struct print_entry, buf);
trace_seq_printf(s, ": %*.s", max, field->buf);
Link: https://lore.kernel.org/linux-trace-kernel/20231212084444.4619b8ce@gandalf.local.home
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Reviewed-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
|
|
There is a selftest that checks if FPRs are corrupted across a fork, aka
clone. It was added as part of the series that optimised the clone path
to save the parent's FP state without "giving up" (turning off FP).
See commit 8792468da5e1 ("powerpc: Add the ability to save FPU without
giving it up").
The test encodes the assumption that FPRs 0-13 are volatile across the
syscall, by only checking the volatile FPRs are not changed by the fork.
There was also a comment in the fpu_preempt test alluding to that:
The check_fpu function in asm only checks the non volatile registers
as it is reused from the syscall test
It is true that the function call ABI treats f0-f13 as volatile,
however the syscall ABI has since been documented as *not* treating those
registers as volatile. See commit 7b8845a2a2ec ("powerpc/64: Document
the syscall ABI").
So change the test to check all FPRs are not corrupted by the syscall.
Note that this currently fails, because save_fpu() etc. do not restore
f0/vsr0.
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20231128132748.1990179-5-mpe@ellerman.id.au
|
|
The FPU preempt test only runs for 20 seconds, which is not particularly
long. Run it for 60 seconds to increase the chance of detecting
corruption.
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20231128132748.1990179-4-mpe@ellerman.id.au
|
|
The fpu_preempt test randomly initialises an array of doubles to try and
detect FPU register corruption.
However the values it generates do not occupy the full range of values
possible in the 64-bit double, meaning some partial register corruption
could go undetected.
Without getting too carried away, add some better initialisation to
generate values that occupy more bits.
Sample values before:
f0 902677510 (raw 0x41cae6e203000000)
f1 325217596 (raw 0x41b3626d3c000000)
f2 1856578300 (raw 0x41dbaa48bf000000)
f3 1247189984 (raw 0x41d295a6f8000000)
And after:
f0 1.1078153481413311e-09 (raw 0x3e13083932805cc2)
f1 1.0576648474801922e+17 (raw 0x43777c20eb88c261)
f2 -6.6245033413594075e-10 (raw 0xbe06c2f989facae9)
f3 3.0085988827156291e+18 (raw 0x43c4e0585f2df37b)
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20231128132748.1990179-3-mpe@ellerman.id.au
|
|
There's a selftest that checks FPRs aren't corrupted by preemption, or
just process scheduling. However it only checks the non-volatile FPRs,
meaning corruption of the volatile FPRs could go undetected.
The check_fpu function it calls is used by several other tests, so for
now add a new routine to check all the FPRs. Increase the size of the
array of FPRs to 32, and initialise them all with random values.
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20231128132748.1990179-2-mpe@ellerman.id.au
|
|
The FPU & VMX preemption tests do not check for errors returned by the
low-level asm routines, preempt_fpu() / preempt_vsx() respectively.
That means any register corruption detected by the asm routines does not
result in a test failure.
Fix it by returning the return value of the asm routines from the
pthread child routines.
Fixes: e5ab8be68e44 ("selftests/powerpc: Test preservation of FPU and VMX regs across preemption")
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20231128132748.1990179-1-mpe@ellerman.id.au
|
|
For the ring buffer iterator (non-consuming read), the event needs to be
copied into the iterator buffer to make sure that a writer does not
overwrite it while the user is reading it. If a write happens during the
copy, the buffer is simply discarded.
But the temp buffer itself was not big enough. The allocation of the
buffer was only BUF_MAX_DATA_SIZE, which is the maximum data size that can
be passed into the ring buffer and saved. But the temp buffer needs to
hold the meta data as well. That would be BUF_PAGE_SIZE and not
BUF_MAX_DATA_SIZE.
Link: https://lore.kernel.org/linux-trace-kernel/20231212072558.61f76493@gandalf.local.home
Cc: stable@vger.kernel.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Fixes: 785888c544e04 ("ring-buffer: Have rb_iter_head_event() handle concurrent writer")
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
|
|
The ring buffer timestamps are synchronized by two timestamp placeholders.
One is the "before_stamp" and the other is the "write_stamp" (sometimes
referred to as the "after stamp" but only in the comments. These two
stamps are key to knowing how to handle nested events coming in with a
lockless system.
When moving across sub-buffers, the before stamp is updated but the write
stamp is not. There's an effort to put back the before stamp to something
that seems logical in case there's nested events. But as the current event
is about to cross sub-buffers, and so will any new nested event that happens,
updating the before stamp is useless, and could even introduce new race
conditions.
The first event on a sub-buffer simply uses the sub-buffer's timestamp
and keeps a "delta" of zero. The "before_stamp" and "write_stamp" are not
used in the algorithm in this case. There's no reason to try to fix the
before_stamp when this happens.
As a bonus, it removes a cmpxchg() when crossing sub-buffers!
Link: https://lore.kernel.org/linux-trace-kernel/20231211114420.36dde01b@gandalf.local.home
Cc: stable@vger.kernel.org
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Fixes: a389d86f7fd09 ("ring-buffer: Have nested events still record running time stamp")
Reviewed-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
|
|
In the effort to reduce zombie memcgs [1], it was discovered that the
memcg LRU doesn't apply enough pressure on offlined memcgs. Specifically,
instead of rotating them to the tail of the current generation
(MEMCG_LRU_TAIL) for a second attempt, it moves them to the next
generation (MEMCG_LRU_YOUNG) after the first attempt.
Not applying enough pressure on offlined memcgs can cause them to build
up, and this can be particularly harmful to memory-constrained systems.
On Pixel 8 Pro, launching apps for 50 cycles:
Before After Change
Zombie memcgs 45 35 -22%
[1] https://lore.kernel.org/CABdmKX2M6koq4Q0Cmp_-=wbP0Qa190HdEGGaHfxNS05gAkUtPA@mail.gmail.com/
Link: https://lkml.kernel.org/r/20231208061407.2125867-4-yuzhao@google.com
Fixes: e4dde56cd208 ("mm: multi-gen LRU: per-node lru_gen_folio lists")
Signed-off-by: Yu Zhao <yuzhao@google.com>
Reported-by: T.J. Mercier <tjmercier@google.com>
Tested-by: T.J. Mercier <tjmercier@google.com>
Cc: Charan Teja Kalla <quic_charante@quicinc.com>
Cc: Hillf Danton <hdanton@sina.com>
Cc: Jaroslav Pulchart <jaroslav.pulchart@gooddata.com>
Cc: Kairui Song <ryncsn@gmail.com>
Cc: Kalesh Singh <kaleshsingh@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
While investigating kswapd "consuming 100% CPU" [1] (also see "mm/mglru:
try to stop at high watermarks"), it was discovered that the memcg LRU can
breach the thrashing protection imposed by min_ttl_ms.
Before the memcg LRU:
kswapd()
shrink_node_memcgs()
mem_cgroup_iter()
inc_max_seq() // always hit a different memcg
lru_gen_age_node()
mem_cgroup_iter()
check the timestamp of the oldest generation
After the memcg LRU:
kswapd()
shrink_many()
restart:
iterate the memcg LRU:
inc_max_seq() // occasionally hit the same memcg
if raced with lru_gen_rotate_memcg():
goto restart
lru_gen_age_node()
mem_cgroup_iter()
check the timestamp of the oldest generation
Specifically, when the restart happens in shrink_many(), it needs to stick
with the (memcg LRU) generation it began with. In other words, it should
neither re-read memcg_lru->seq nor age an lruvec of a different
generation. Otherwise it can hit the same memcg multiple times without
giving lru_gen_age_node() a chance to check the timestamp of that memcg's
oldest generation (against min_ttl_ms).
[1] https://lore.kernel.org/CAK8fFZ4DY+GtBA40Pm7Nn5xCHy+51w3sfxPqkqpqakSXYyX+Wg@mail.gmail.com/
Link: https://lkml.kernel.org/r/20231208061407.2125867-3-yuzhao@google.com
Fixes: e4dde56cd208 ("mm: multi-gen LRU: per-node lru_gen_folio lists")
Signed-off-by: Yu Zhao <yuzhao@google.com>
Tested-by: T.J. Mercier <tjmercier@google.com>
Cc: Charan Teja Kalla <quic_charante@quicinc.com>
Cc: Hillf Danton <hdanton@sina.com>
Cc: Jaroslav Pulchart <jaroslav.pulchart@gooddata.com>
Cc: Kairui Song <ryncsn@gmail.com>
Cc: Kalesh Singh <kaleshsingh@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
The initial MGLRU patchset didn't include the memcg LRU support, and it
relied on should_abort_scan(), added by commit f76c83378851 ("mm:
multi-gen LRU: optimize multiple memcgs"), to "backoff to avoid
overshooting their aggregate reclaim target by too much".
Later on when the memcg LRU was added, should_abort_scan() was deemed
unnecessary, and the test results [1] showed no side effects after it was
removed by commit a579086c99ed ("mm: multi-gen LRU: remove eviction
fairness safeguard").
However, that test used memory.reclaim, which sets nr_to_reclaim to
SWAP_CLUSTER_MAX. So it can overshoot only by SWAP_CLUSTER_MAX-1 pages,
i.e., from nr_reclaimed=nr_to_reclaim-1 to
nr_reclaimed=nr_to_reclaim+SWAP_CLUSTER_MAX-1. Compared with the batch
size kswapd sets to nr_to_reclaim, SWAP_CLUSTER_MAX is tiny. Therefore
that test isn't able to reproduce the worst case scenario, i.e., kswapd
overshooting GBs on large systems and "consuming 100% CPU" (see the Closes
tag).
Bring back a simplified version of should_abort_scan() on top of the memcg
LRU, so that kswapd stops when all eligible zones are above their
respective high watermarks plus a small delta to lower the chance of
KSWAPD_HIGH_WMARK_HIT_QUICKLY. Note that this only applies to order-0
reclaim, meaning compaction-induced reclaim can still run wild (which is a
different problem).
On Android, launching 55 apps sequentially:
Before After Change
pgpgin 838377172 802955040 -4%
pgpgout 38037080 34336300 -10%
[1] https://lore.kernel.org/20221222041905.2431096-1-yuzhao@google.com/
Link: https://lkml.kernel.org/r/20231208061407.2125867-2-yuzhao@google.com
Fixes: a579086c99ed ("mm: multi-gen LRU: remove eviction fairness safeguard")
Signed-off-by: Yu Zhao <yuzhao@google.com>
Reported-by: Charan Teja Kalla <quic_charante@quicinc.com>
Reported-by: Jaroslav Pulchart <jaroslav.pulchart@gooddata.com>
Closes: https://lore.kernel.org/CAK8fFZ4DY+GtBA40Pm7Nn5xCHy+51w3sfxPqkqpqakSXYyX+Wg@mail.gmail.com/
Tested-by: Jaroslav Pulchart <jaroslav.pulchart@gooddata.com>
Tested-by: Kalesh Singh <kaleshsingh@google.com>
Cc: Hillf Danton <hdanton@sina.com>
Cc: Kairui Song <ryncsn@gmail.com>
Cc: T.J. Mercier <tjmercier@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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