kernel.git/drivers/base/power/sysfs.c, branch linux-4.19.y

Revert "drivers core: Use sysfs_emit and sysfs_emit_at for show(device *...) functions"

2023-10-10T19:45:00Z

This reverts commit 3ce2cd63e8ee037644db0cbea65e6c40ab6cc178 which is commit aa838896d87af561a33ecefea1caa4c15a68bc47 upstream. Ben writes: When I looked into the referenced security issue, it seemed to only be exploitable through wakelock names, and in the upstream kernel only after commit c8377adfa781 "PM / wakeup: Show wakeup sources stats in sysfs" (first included in 5.4). So I would be interested to know if and why a fix was needed for 4.19. More importantly, this backported version uniformly converts to sysfs_emit(), but there are 3 places sysfs_emit_at() must be used instead: Reported-by: Ben Hutchings Link: https://lore.kernel.org/r/95831df76c41a53bc3e1ac8ece64915dd63763a1.camel@decadent.org.uk Cc: Joe Perches Cc: Brennan Lamoreaux Signed-off-by: Greg Kroah-Hartman

drivers core: Use sysfs_emit and sysfs_emit_at for show(device *...) functions

2023-08-11T09:45:40Z

commit aa838896d87af561a33ecefea1caa4c15a68bc47 upstream. Convert the various sprintf fmaily calls in sysfs device show functions to sysfs_emit and sysfs_emit_at for PAGE_SIZE buffer safety. Done with: $ spatch -sp-file sysfs_emit_dev.cocci --in-place --max-width=80 . And cocci script: $ cat sysfs_emit_dev.cocci @@ identifier d_show; identifier dev, attr, buf; @@ ssize_t d_show(struct device *dev, struct device_attribute *attr, char *buf) { <... return - sprintf(buf, + sysfs_emit(buf, ...); ...> } @@ identifier d_show; identifier dev, attr, buf; @@ ssize_t d_show(struct device *dev, struct device_attribute *attr, char *buf) { <... return - snprintf(buf, PAGE_SIZE, + sysfs_emit(buf, ...); ...> } @@ identifier d_show; identifier dev, attr, buf; @@ ssize_t d_show(struct device *dev, struct device_attribute *attr, char *buf) { <... return - scnprintf(buf, PAGE_SIZE, + sysfs_emit(buf, ...); ...> } @@ identifier d_show; identifier dev, attr, buf; expression chr; @@ ssize_t d_show(struct device *dev, struct device_attribute *attr, char *buf) { <... return - strcpy(buf, chr); + sysfs_emit(buf, chr); ...> } @@ identifier d_show; identifier dev, attr, buf; identifier len; @@ ssize_t d_show(struct device *dev, struct device_attribute *attr, char *buf) { <... len = - sprintf(buf, + sysfs_emit(buf, ...); ...> return len; } @@ identifier d_show; identifier dev, attr, buf; identifier len; @@ ssize_t d_show(struct device *dev, struct device_attribute *attr, char *buf) { <... len = - snprintf(buf, PAGE_SIZE, + sysfs_emit(buf, ...); ...> return len; } @@ identifier d_show; identifier dev, attr, buf; identifier len; @@ ssize_t d_show(struct device *dev, struct device_attribute *attr, char *buf) { <... len = - scnprintf(buf, PAGE_SIZE, + sysfs_emit(buf, ...); ...> return len; } @@ identifier d_show; identifier dev, attr, buf; identifier len; @@ ssize_t d_show(struct device *dev, struct device_attribute *attr, char *buf) { <... - len += scnprintf(buf + len, PAGE_SIZE - len, + len += sysfs_emit_at(buf, len, ...); ...> return len; } @@ identifier d_show; identifier dev, attr, buf; expression chr; @@ ssize_t d_show(struct device *dev, struct device_attribute *attr, char *buf) { ... - strcpy(buf, chr); - return strlen(buf); + return sysfs_emit(buf, chr); } Signed-off-by: Joe Perches Link: https://lore.kernel.org/r/3d033c33056d88bbe34d4ddb62afd05ee166ab9a.1600285923.git.joe@perches.com [ Brennan : Regenerated for 4.19 to fix CVE-2022-20166 ] Signed-off-by: Brennan Lamoreaux Signed-off-by: Greg Kroah-Hartman

PM / wakeup: Export wakeup_count instead of event_count via sysfs

2018-06-06T07:23:36Z

Currently we export event_count instead of wakeup_count via the per-device wakeup_count sysfs attribute. Change it to wakeup_count to make it more meaningful. wakeup_count increments only when events_check_enabled is set, that is whenever writes the current wakeup count to /sys/power/wakeup_count. Also events_check_enabled is cleared on every resume. User space is expected to write to this just before suspend. This way pm_wakeup_event(), when called from IRQs handles, will increment wakeup_count only if we are in system-wide suspend-resume cycle and should give a fair approximation of how many times a device may have triggered a wakeup from system suspend. event_count on the other hand will increment every time pm_wakeup_event() is called irrespective of whether we are in a suspend-resume cycle and some drivers call it on every interrupt which makes it less useful for system wakeup tracking. Signed-off-by: Ravi Chandra Sadineni Acked-by: Pavel Machek [ rjw: Subject & changelog ] Signed-off-by: Rafael J. Wysocki

PM / sysfs: Convert to use DEVICE_ATTR_RO / DEVICE_ATTR_RW

2017-12-05T00:59:57Z

Use DEVICE_ATTR_RO() and DEVICE_ATTR_RW() macros instead of open coding them. No functional change intended. Signed-off-by: Andy Shevchenko Acked-by: Pavel Machek Signed-off-by: Rafael J. Wysocki

PM / sysfs: Remove redundant 'else' keyword.

2017-12-05T00:59:57Z

There is no need to use 'else' if in main branch 'return' is present. No functional change intended. Signed-off-by: Andy Shevchenko Acked-by: Pavel Machek Signed-off-by: Rafael J. Wysocki

PM / sysfs: Convert to use sysfs_streq()

2017-12-05T00:59:56Z

...instead of custom approach. Signed-off-by: Andy Shevchenko Acked-by: Pavel Machek Signed-off-by: Rafael J. Wysocki

PM / QoS: Fix device resume latency framework

2017-11-08T11:14:51Z

The special value of 0 for device resume latency PM QoS means "no restriction", but there are two problems with that. First, device resume latency PM QoS requests with 0 as the value are always put in front of requests with positive values in the priority lists used internally by the PM QoS framework, causing 0 to be chosen as an effective constraint value. However, that 0 is then interpreted as "no restriction" effectively overriding the other requests with specific restrictions which is incorrect. Second, the users of device resume latency PM QoS have no way to specify that *any* resume latency at all should be avoided, which is an artificial limitation in general. To address these issues, modify device resume latency PM QoS to use S32_MAX as the "no constraint" value and 0 as the "no latency at all" one and rework its users (the cpuidle menu governor, the genpd QoS governor and the runtime PM framework) to follow these changes. Also add a special "n/a" value to the corresponding user space I/F to allow user space to indicate that it cannot accept any resume latencies at all for the given device. Fixes: 85dc0b8a4019 (PM / QoS: Make it possible to expose PM QoS latency constraints) Link: https://bugzilla.kernel.org/show_bug.cgi?id=197323 Reported-by: Reinette Chatre Signed-off-by: Rafael J. Wysocki Tested-by: Reinette Chatre Tested-by: Geert Uytterhoeven Tested-by: Tero Kristo Reviewed-by: Ramesh Thomas

PM / QoS: Drop PM_QOS_FLAG_REMOTE_WAKEUP

2017-10-13T23:04:31Z

The PM QoS flag PM_QOS_FLAG_REMOTE_WAKEUP is not used consistently and the vast majority of code simply assumes that remote wakeup should be enabled for devices in runtime suspend if they can generate wakeup signals, so drop it. Signed-off-by: Rafael J. Wysocki Acked-by: Ulf Hansson Reviewed-by: Mika Westerberg

PM / QoS: return -EINVAL for bogus strings

2017-07-12T12:42:37Z

In the current code, if the user accidentally writes a bogus command to this sysfs file, then we set the latency tolerance to an uninitialized variable. Fixes: 2d984ad132a8 (PM / QoS: Introcuce latency tolerance device PM QoS type) Signed-off-by: Dan Carpenter Acked-by: Pavel Machek Cc: 3.15+ # 3.15+ Signed-off-by: Rafael J. Wysocki

PM / QoS: constify *_attribute_group.

2017-06-27T22:45:25Z

File size before: text data bss dec hex filename 3890 1152 8 5050 13ba drivers/base/power/sysfs.o File size After adding 'const': text data bss dec hex filename 4250 800 8 5058 13c2 drivers/base/power/sysfs.o Signed-off-by: Arvind Yadav Acked-by: Pavel Machek Signed-off-by: Rafael J. Wysocki