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https://github.com/SCST-project/scst.git
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Bart Van Assche
4107c7164f
For any qla2xxx async command, the SRB buffer is used to send it. In
setting up the SRB buffer, the timer for this command is started before all
memory allocation has finished. Under low memory pressure, memory alloc
can go to sleep and not wake up before the timer expires. Once timer has
expired, the timer thread will access uninitialize fields resulting into
NULL pointer crash.
This patch fixes this crash by moving the start of timer after everything
is setup.
backtrace shows following
PID: 3720 TASK: ffff996928401040 CPU: 0 COMMAND: "qla2xxx_1_dpc"
0 [ffff99652751b698] __schedule at ffffffff965676c7
1 [ffff99652751b728] schedule at ffffffff96567bc9
2 [ffff99652751b738] schedule_timeout at ffffffff965655e8
3 [ffff99652751b7e0] io_schedule_timeout at ffffffff9656726d
4 [ffff99652751b810] congestion_wait at ffffffff95fd8d12
5 [ffff99652751b870] isolate_migratepages_range at ffffffff95fddaf3
6 [ffff99652751b930] compact_zone at ffffffff95fdde96
7 [ffff99652751b980] compact_zone_order at ffffffff95fde0bc
8 [ffff99652751ba20] try_to_compact_pages at ffffffff95fde481
9 [ffff99652751ba80] __alloc_pages_direct_compact at ffffffff9655cc31
10 [ffff99652751bae0] __alloc_pages_slowpath at ffffffff9655d101
11 [ffff99652751bbd0] __alloc_pages_nodemask at ffffffff95fc0e95
12 [ffff99652751bc80] dma_generic_alloc_coherent at ffffffff95e3217f
13 [ffff99652751bcc8] x86_swiotlb_alloc_coherent at ffffffff95e6b7a1
14 [ffff99652751bcf8] qla2x00_rft_id at ffffffffc055b5e0 [qla2xxx]
15 [ffff99652751bd50] qla2x00_loop_resync at ffffffffc0533e71 [qla2xxx]
16 [ffff99652751be68] qla2x00_do_dpc at ffffffffc05210ca [qla2xxx]
PID: 0 TASK: ffffffff96a18480 CPU: 0 COMMAND: "swapper/0"
0 [ffff99652fc03ae0] machine_kexec at ffffffff95e63674
1 [ffff99652fc03b40] __crash_kexec at ffffffff95f1ce12
2 [ffff99652fc03c10] crash_kexec at ffffffff95f1cf00
3 [ffff99652fc03c28] oops_end at ffffffff9656c758
4 [ffff99652fc03c50] no_context at ffffffff9655aa7e
5 [ffff99652fc03ca0] __bad_area_nosemaphore at ffffffff9655ab15
6 [ffff99652fc03cf0] bad_area_nosemaphore at ffffffff9655ac86
7 [ffff99652fc03d00] __do_page_fault at ffffffff9656f6b0
8 [ffff99652fc03d70] do_page_fault at ffffffff9656f915
9 [ffff99652fc03da0] page_fault at ffffffff9656b758
[exception RIP: unknown or invalid address]
RIP: 0000000000000000 RSP: ffff99652fc03e50 RFLAGS: 00010202
RAX: 0000000000000000 RBX: ffff99652b79a600 RCX: ffff99652b79a760
RDX: ffff99652b79a600 RSI: ffffffffc0525ad0 RDI: ffff99652b79a600
RBP: ffff99652fc03e60 R8: ffffffff96a18a18 R9: ffffffff96ee3c00
R10: 0000000000000002 R11: ffff99652fc03de8 R12: ffff99652b79a760
R13: 0000000000000100 R14: ffffffffc0525ad0 R15: ffff99652b79a600
ORIG_RAX: ffffffffffffffff CS: 0010 SS: 0018
10 [ffff99652fc03e50] qla2x00_sp_timeout at ffffffffc0525af8 [qla2xxx]
11 [ffff99652fc03e68] call_timer_fn at ffffffff95ea7f58
12 [ffff99652fc03ea0] run_timer_softirq at ffffffff95eaa3bd
13 [ffff99652fc03f18] __do_softirq at ffffffff95ea0f05
14 [ffff99652fc03f88] call_softirq at ffffffff9657832c
15 [ffff99652fc03fa0] do_softirq at ffffffff95e2e675
16 [ffff99652fc03fc0] irq_exit at ffffffff95ea1285
17 [ffff99652fc03fd8] smp_apic_timer_interrupt at ffffffff965796c8
18 [ffff99652fc03ff0] apic_timer_interrupt at ffffffff96575df2
[ commit 3a4b6cc7332130ac5cbf3b505d8cddf0aa2ea745 upstream ]
git-svn-id: http://svn.code.sf.net/p/scst/svn/trunk@8530 d57e44dd-8a1f-0410-8b47-8ef2f437770f
Overview ======== This is the SCST development repository. It contains not a single project SCST as one can think, but a number of them, which are divided as the following: 1. SCST core in scst/ subdirectory 2. Administration utility for SCST core scstadmin in scstadmin/ 3. Target drivers in own subdirectories qla2x00t/, iscsi-scst/, etc. 4. User space programs in usr/ subdirectory, like fileio_tgt. 5. Some various docs in doc/ subdirectory. Those subprojects are in most cases independent from each other, although some of them depend from the SCST core. They put in the single repository only to simplify their development, they are released independently. Thus, use "make all" only if you really need to build everything. Otherwise build only what you need, like for iSCSI-SCST: make scst scst_install iscsi iscsi_install For more information about each subproject see their README files. QLogic target driver ==================== QLogic target driver qla2x00t is the old driver, forked from qla2xxx several years ago. It is very stable, well tested and actively used in many production setups. There is also new driver, maintained by QLogic, which, among other, supports 32G FC, see http://scst.sourceforge.net/target_qla2x00t.html. You can find the latest version of it in git://git.qlogic.com/scst-qla2xxx.git. To integrate it into the SCST build tree you need to clone the QLogic git tree in a subdirectory of this directory (SCST root tree) with name qla2x00t_git (or create a symlink with this name pointing to any other location in your system). Now common and QLA specific root Makefile targets "magically" start working with the new driver. Then follow instructions in the git's README. In presence of qla2x00t_git subdirectory you can still build the qla2x00t using qla_old* root Makefile targets. Vladislav Bolkhovitin <vst@vlnb.net>, http://scst.sourceforge.net