kernel/linux.git/arch/powerpc/include/asm/fadump.h, branch linux-4.4.y

powerpc/fadump: handle crash memory ranges array index overflow

2018-09-09T18:04:32+00:00

commit 1bd6a1c4b80a28d975287630644e6b47d0f977a5 upstream. Crash memory ranges is an array of memory ranges of the crashing kernel to be exported as a dump via /proc/vmcore file. The size of the array is set based on INIT_MEMBLOCK_REGIONS, which works alright in most cases where memblock memory regions count is less than INIT_MEMBLOCK_REGIONS value. But this count can grow beyond INIT_MEMBLOCK_REGIONS value since commit 142b45a72e22 ("memblock: Add array resizing support"). On large memory systems with a few DLPAR operations, the memblock memory regions count could be larger than INIT_MEMBLOCK_REGIONS value. On such systems, registering fadump results in crash or other system failures like below: task: c00007f39a290010 ti: c00000000b738000 task.ti: c00000000b738000 NIP: c000000000047df4 LR: c0000000000f9e58 CTR: c00000000010f180 REGS: c00000000b73b570 TRAP: 0300 Tainted: G L X (4.4.140+) MSR: 8000000000009033 CR: 22004484 XER: 20000000 CFAR: c000000000008500 DAR: 000007a450000000 DSISR: 40000000 SOFTE: 0 ... NIP [c000000000047df4] smp_send_reschedule+0x24/0x80 LR [c0000000000f9e58] resched_curr+0x138/0x160 Call Trace: resched_curr+0x138/0x160 (unreliable) check_preempt_curr+0xc8/0xf0 ttwu_do_wakeup+0x38/0x150 try_to_wake_up+0x224/0x4d0 __wake_up_common+0x94/0x100 ep_poll_callback+0xac/0x1c0 __wake_up_common+0x94/0x100 __wake_up_sync_key+0x70/0xa0 sock_def_readable+0x58/0xa0 unix_stream_sendmsg+0x2dc/0x4c0 sock_sendmsg+0x68/0xa0 ___sys_sendmsg+0x2cc/0x2e0 __sys_sendmsg+0x5c/0xc0 SyS_socketcall+0x36c/0x3f0 system_call+0x3c/0x100 as array index overflow is not checked for while setting up crash memory ranges causing memory corruption. To resolve this issue, dynamically allocate memory for crash memory ranges and resize it incrementally, in units of pagesize, on hitting array size limit. Fixes: 2df173d9e85d ("fadump: Initialize elfcore header and add PT_LOAD program headers.") Cc: stable@vger.kernel.org # v3.4+ Signed-off-by: Hari Bathini Reviewed-by: Mahesh Salgaonkar [mpe: Just use PAGE_SIZE directly, fixup variable placement] Signed-off-by: Michael Ellerman Signed-off-by: Greg Kroah-Hartman

powerpc/fadump: Fix endianess issues in firmware assisted dump handling

2014-10-30T05:52:46+00:00

Firmware-assisted dump (fadump) kernel code is not endian safe. The below patch fixes this issue. Tested this patch with upstream kernel. Below output shows crash tool successfully opening LE fadump vmcore. # crash vmlinux vmcore GNU gdb (GDB) 7.6 This GDB was configured as "powerpc64le-unknown-linux-gnu"... KERNEL: vmlinux DUMPFILE: vmcore CPUS: 16 DATE: Wed Dec 31 19:00:00 1969 UPTIME: 00:03:28 LOAD AVERAGE: 0.46, 0.86, 0.41 TASKS: 268 NODENAME: linux-dhr2 RELEASE: 3.17.0-rc5-7-default VERSION: #6 SMP Tue Sep 30 01:06:34 EDT 2014 MACHINE: ppc64le (4116 Mhz) MEMORY: 40 GB PANIC: "Oops: Kernel access of bad area, sig: 11 [#1]" (check log for details) PID: 6223 COMMAND: "bash" TASK: c0000009661b2500 [THREAD_INFO: c000000967ac0000] CPU: 2 STATE: TASK_RUNNING (PANIC) Signed-off-by: Hari Bathini [mpe: Make the comment in pSeries_lpar_hptab_clear() clearer] Signed-off-by: Michael Ellerman

include/linux/crash_dump.h: add vmcore_cleanup() prototype

2014-04-07T23:36:06+00:00

Eliminate the following warning in proc/vmcore.c: fs/proc/vmcore.c:1088:6: warning: no previous prototype for `vmcore_cleanup' [-Wmissing-prototypes] [akpm@linux-foundation.org: clean up powerpc, remove unneeded EXPORT_SYMBOL] Signed-off-by: Rashika Kheria Reviewed-by: Josh Triplett Cc: Benjamin Herrenschmidt Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

fadump: Invalidate registration and release reserved memory for general use.

2012-02-22T23:50:02+00:00

This patch introduces an sysfs interface '/sys/kernel/fadump_release_mem' to invalidate the last fadump registration, invalidate '/proc/vmcore', release the reserved memory for general use and re-register for future kernel dump. Once the dump is copied to the disk, unlike phyp dump, the userspace tool can release all the memory reserved for dump with one single operation of echo 1 to '/sys/kernel/fadump_release_mem'. Release the reserved memory region excluding the size of the memory required for future kernel dump registration. And therefore, unlike kdump, Fadump doesn't need a 2nd reboot to get back the system to the production configuration. Signed-off-by: Mahesh Salgaonkar Signed-off-by: Benjamin Herrenschmidt

fadump: Convert firmware-assisted cpu state dump data into elf notes.

2012-02-22T23:50:01+00:00

When registered for firmware assisted dump on powerpc, firmware preserves the registers for the active CPUs during a system crash. This patch reads the cpu register data stored in Firmware-assisted dump format (except for crashing cpu) and converts it into elf notes and updates the PT_NOTE program header accordingly. The exact register state for crashing cpu is saved to fadump crash info structure in scratch area during crash_fadump() and read during second kernel boot. Signed-off-by: Mahesh Salgaonkar Signed-off-by: Benjamin Herrenschmidt

fadump: Initialize elfcore header and add PT_LOAD program headers.

2012-02-22T23:50:01+00:00

Build the crash memory range list by traversing through system memory during the first kernel before we register for firmware-assisted dump. After the successful dump registration, initialize the elfcore header and populate PT_LOAD program headers with crash memory ranges. The elfcore header is saved in the scratch area within the reserved memory. The scratch area starts at the end of the memory reserved for saving RMR region contents. The scratch area contains fadump crash info structure that contains magic number for fadump validation and physical address where the eflcore header can be found. This structure will also be used to pass some important crash info data to the second kernel which will help second kernel to populate ELF core header with correct data before it gets exported through /proc/vmcore. Since the firmware preserves the entire partition memory at the time of crash the contents of the scratch area will be preserved till second kernel boot. Since the memory dump exported through /proc/vmcore is in ELF format similar to kdump, it will help us to reuse the kdump infrastructure for dump capture and filtering. Unlike phyp dump, userspace tool does not need to refer any sysfs interface while reading /proc/vmcore. NOTE: The current design implementation does not address a possibility of introducing additional fields (in future) to this structure without affecting compatibility. It's on TODO list to come up with better approach to address this. Reserved dump area start => +-------------------------------------+ | CPU state dump data | +-------------------------------------+ | HPTE region data | +-------------------------------------+ | RMR region data | Scratch area start => +-------------------------------------+ | fadump crash info structure { | | magic nummber | +------|---- elfcorehdr_addr | | | } | +----> +-------------------------------------+ | ELF core header | Reserved dump area end => +-------------------------------------+ Signed-off-by: Mahesh Salgaonkar Signed-off-by: Benjamin Herrenschmidt

fadump: Register for firmware assisted dump.

2012-02-22T23:50:01+00:00

On 2012-02-20 11:02:51 Mon, Paul Mackerras wrote: > On Thu, Feb 16, 2012 at 04:44:30PM +0530, Mahesh J Salgaonkar wrote: > > If I have read the code correctly, we are going to get this printk on > non-pSeries machines or on older pSeries machines, even if the user > has not put the fadump=on option on the kernel command line. The > printk will be annoying since there is no actual error condition. It > seems to me that the condition for the printk should include > fw_dump.fadump_enabled. In other words you should probably add > > if (!fw_dump.fadump_enabled) > return 0; > > at the beginning of the function. Hi Paul, Thanks for pointing it out. Please find the updated patch below. The existing patches above this (4/10 through 10/10) cleanly applies on this update. Thanks, -Mahesh. Signed-off-by: Benjamin Herrenschmidt

fadump: Reserve the memory for firmware assisted dump.

2012-02-22T23:50:01+00:00

Reserve the memory during early boot to preserve CPU state data, HPTE region and RMA (real mode area) region data in case of kernel crash. At the time of crash, powerpc firmware will store CPU state data, HPTE region data and move RMA region data to the reserved memory area. If the firmware-assisted dump fails to reserve the memory, then fallback to existing kexec-based kdump. Most of the code implementation to reserve memory has been adapted from phyp assisted dump implementation written by Linas Vepstas and Manish Ahuja This patch also introduces a config option CONFIG_FA_DUMP for firmware assisted dump feature on Powerpc (ppc64) architecture. Signed-off-by: Mahesh Salgaonkar Signed-off-by: Benjamin Herrenschmidt