linux/kernel/irq/proc.c, branch v3.19

genirq: Prevent proc race against freeing of irq descriptors

2014-12-13T12:33:07Z

Since the rework of the sparse interrupt code to actually free the unused interrupt descriptors there exists a race between the /proc interfaces to the irq subsystem and the code which frees the interrupt descriptor. CPU0 CPU1 show_interrupts() desc = irq_to_desc(X); free_desc(desc) remove_from_radix_tree(); kfree(desc); raw_spinlock_irq(&desc->lock); /proc/interrupts is the only interface which can actively corrupt kernel memory via the lock access. /proc/stat can only read from freed memory. Extremly hard to trigger, but possible. The interfaces in /proc/irq/N/ are not affected by this because the removal of the proc file is serialized in procfs against concurrent readers/writers. The removal happens before the descriptor is freed. For architectures which have CONFIG_SPARSE_IRQ=n this is a non issue as the descriptor is never freed. It's merely cleared out with the irq descriptor lock held. So any concurrent proc access will either see the old correct value or the cleared out ones. Protect the lookup and access to the irq descriptor in show_interrupts() with the sparse_irq_lock. Provide kstat_irqs_usr() which is protecting the lookup and access with sparse_irq_lock and switch /proc/stat to use it. Document the existing kstat_irqs interfaces so it's clear that the caller needs to take care about protection. The users of these interfaces are either not affected due to SPARSE_IRQ=n or already protected against removal. Fixes: 1f5a5b87f78f "genirq: Implement a sane sparse_irq allocator" Signed-off-by: Thomas Gleixner Cc: stable@vger.kernel.org

genirq: procfs: Make smp_affinity values go+r

2014-03-19T11:34:29Z

Includes: - /proc/irq/default_smp_affinity - /proc/irq/*/affinity_hint - /proc/irq/*/smp_affinity - /proc/irq/*/smp_affinity_list Users can distill the same information by reading /proc/interrupts. Signed-off-by: Chema Gonzalez Cc: Eric Dumazet Link: http://lkml.kernel.org/r/1394765455-1217-1-git-send-email-chema@google.com Signed-off-by: Thomas Gleixner

irqdomain: Include hwirq number in /proc/interrupts

2013-06-24T13:02:42Z

Add the hardware interrupt number to the output of /proc/interrupts. It is often important to have access to the hardware interrupt number because it identifies exactly how an interrupt signal is wired up to the interrupt controller. This is especially important when using irq_domains since irq numbers get dynamically allocated in that case, and have no relation to the actual hardware number. Note: This output is currently conditional on whether or not the irq_domain pointer is set; however hwirq could still be used without irq_domain. It may be worthwhile to always output the hwirq number regardless of the domain pointer. Signed-off-by: Grant Likely Tested-by: Olof Johansson Cc: Ben Herrenschmidt Cc: Thomas Gleixner

proc: Supply a function to remove a proc entry by PDE

2013-05-01T21:29:46Z

Supply a function (proc_remove()) to remove a proc entry (and any subtree rooted there) by proc_dir_entry pointer rather than by name and (optionally) root dir entry pointer. This allows us to eliminate all remaining pde->name accesses outside of procfs. Signed-off-by: David Howells Acked-by: Grant Likely cc: linux-acpi@vger.kernel.org cc: openipmi-developer@lists.sourceforge.net cc: devicetree-discuss@lists.ozlabs.org cc: linux-pci@vger.kernel.org cc: netdev@vger.kernel.org cc: netfilter-devel@vger.kernel.org cc: alsa-devel@alsa-project.org Signed-off-by: Al Viro

procfs: new helper - PDE_DATA(inode)

2013-04-09T18:13:32Z

The only part of proc_dir_entry the code outside of fs/proc really cares about is PDE(inode)->data. Provide a helper for that; static inline for now, eventually will be moved to fs/proc, along with the knowledge of struct proc_dir_entry layout. Signed-off-by: Al Viro

new helper: file_inode(file)

2013-02-23T04:31:31Z

Signed-off-by: Al Viro

irq: Remove smp_affinity_list when unregister irq proc

2011-05-26T11:15:28Z

commit 4b06042(bitmap, irq: add smp_affinity_list interface to /proc/irq) causes the following warning: [ 274.239500] WARNING: at fs/proc/generic.c:850 remove_proc_entry+0x24c/0x27a() [ 274.251761] remove_proc_entry: removing non-empty directory 'irq/184', leaking at least 'smp_affinity_list' Remove the new file in the exit path. Signed-off-by: Yinghai Lu Cc: Mike Travis Link: http://lkml.kernel.org/r/4DDDE094.6050505@kernel.org Signed-off-by: Thomas Gleixner

bitmap, irq: add smp_affinity_list interface to /proc/irq

2011-05-25T15:39:45Z

Manually adjusting the smp_affinity for IRQ's becomes unwieldy when the cpu count is large. Setting smp affinity to cpus 256 to 263 would be: echo 000000ff,00000000,00000000,00000000,00000000,00000000,00000000,00000000 > smp_affinity instead of: echo 256-263 > smp_affinity_list Think about what it looks like for cpus around say, 4088 to 4095. We already have many alternate "list" interfaces: /sys/devices/system/cpu/cpuX/indexY/shared_cpu_list /sys/devices/system/cpu/cpuX/topology/thread_siblings_list /sys/devices/system/cpu/cpuX/topology/core_siblings_list /sys/devices/system/node/nodeX/cpulist /sys/devices/pci***/***/local_cpulist Add a companion interface, smp_affinity_list to use cpu lists instead of cpu maps. This conforms to other companion interfaces where both a map and a list interface exists. This required adding a bitmap_parselist_user() function in a manner similar to the bitmap_parse_user() function. [akpm@linux-foundation.org: make __bitmap_parselist() static] Signed-off-by: Mike Travis Cc: Thomas Gleixner Cc: Jack Steiner Cc: Lee Schermerhorn Cc: Andy Shevchenko Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

genirq: Fix typo CONFIG_GENIRC_IRQ_SHOW_LEVEL

2011-05-02T19:16:37Z

commit ab7798ffcf98b11a9525cf65bacdae3fd58d357f ("genirq: Expand generic show_interrupts()") added the Kconfig option GENERIC_IRQ_SHOW_LEVEL to accomodate PowerPC, but this doesn't actually enable the functionality due to a typo in the #ifdef check. Signed-off-by: Geert Uytterhoeven Cc: Linux/PPC Development Link: http://lkml.kernel.org/r/%3Calpine.DEB.2.00.1104302251370.19068%40ayla.of.borg%3E Signed-off-by: Thomas Gleixner

alpha: Use generic show_interrupts()

2011-03-29T12:47:58Z

The only subtle difference is that alpha uses ACTUAL_NR_IRQS and prints the IRQF_DISABLED flag. Change the generic implementation to deal with ACTUAL_NR_IRQS if defined. The IRQF_DISABLED printing is pointless, as we nowadays run all interrupts with irqs disabled. Signed-off-by: Thomas Gleixner