Hi Lianbo, On Thu, Sep 1, 2022 at 3:28 PM lijiang <liji...@redhat.com> wrote: > > Hi, Tao > Thank you for the fix. > On Thu, Aug 25, 2022 at 8:00 PM <crash-utility-requ...@redhat.com> wrote: >> >> Date: Thu, 25 Aug 2022 14:42:45 +0800 >> From: Tao Liu <l...@redhat.com> >> To: crash-utility@redhat.com >> Subject: [Crash-utility] [PATCH v2] Fix kmem failing to print task >> context when address is vmalloced stack >> Message-ID: <20220825064243.71447-1-l...@redhat.com> >> Content-Type: text/plain; charset="US-ASCII"; x-default=true >> >> When kernel enabled CONFIG_VMAP_STACK, stack can be allocated to >> vmalloced area. Currently crash didn't handle the case, as a result, >> kmem will not print the task context as expected. This patch fix the >> bug by checking if the address is a vmalloced stack first. >> >> Before: >> crash> kmem ffffb7efce9bbe28 >> VMAP_AREA VM_STRUCT ADDRESS RANGE >> SIZE >> ffff94eb9102c640 ffff94eb9102b140 ffffb7efce9b8000 - ffffb7efce9bd000 >> 20480 >> >> PAGE PHYSICAL MAPPING INDEX CNT FLAGS >> ffffdd28220dc000 1883700000 0 0 1 50000000000000 >> >> After: >> crash> kmem ffffb7efce9bbe28 >> PID: 847 >> COMMAND: "khungtaskd" >> TASK: ffff94f8038f4000 [THREAD_INFO: ffff94f8038f4000] >> CPU: 72 >> STATE: TASK_RUNNING (PANIC) >> >> VMAP_AREA VM_STRUCT ADDRESS RANGE >> SIZE >> ffff94eb9102c640 ffff94eb9102b140 ffffb7efce9b8000 - ffffb7efce9bd000 >> 20480 >> > > I have one question: If the given physical address falls in the vmalloc area, > it won't print the task context, is that expected? For example: >
Thanks for pointing it out. Hmm... I didn't consider the physical address case as vtop does. I will improve the patch and send v3. Thanks, Tao Liu > [1] Before this patch: the "kmem + physical/virtual address" has the same > output asbelow. > > crash> kmem ffffb7efce9bbe28 > VMAP_AREA VM_STRUCT ADDRESS RANGE > SIZE > ffff94eb9102c640 ffff94eb9102b140 ffffb7efce9b8000 - ffffb7efce9bd000 > 20480 > > PAGE PHYSICAL MAPPING INDEX CNT FLAGS > ffffdd28220dc000 1883700000 0 0 1 50000000000000 > > crash> kmem 1883700e28 <----- vtop ffffb7efce9bbe28 > VMAP_AREA VM_STRUCT ADDRESS RANGE > SIZE > ffff94eb9102c640 ffff94eb9102b140 ffffb7efce9b8000 - ffffb7efce9bd000 > 20480 > > PAGE PHYSICAL MAPPING INDEX CNT FLAGS > ffffdd28220dc000 1883700000 0 0 1 50000000000000 > > [2] After this patch: the "kmem + physical/virtual address" has different > output asbelow. > crash> kmem ffffb7efce9bbe28 > PID: 847 > COMMAND: "khungtaskd" > TASK: ffff94f8038f4000 [THREAD_INFO: ffff94f8038f4000] > CPU: 72 > STATE: TASK_RUNNING (PANIC) > > VMAP_AREA VM_STRUCT ADDRESS RANGE > SIZE > ffff94eb9102c640 ffff94eb9102b140 ffffb7efce9b8000 - ffffb7efce9bd000 > 20480 > > PAGE PHYSICAL MAPPING INDEX CNT FLAGS > ffffdd28220dc000 1883700000 0 0 1 50000000000000 > > crash> kmem 1883700e28 <----- vtop ffffb7efce9bbe28 > VMAP_AREA VM_STRUCT ADDRESS RANGE > SIZE > ffff94eb9102c640 ffff94eb9102b140 ffffb7efce9b8000 - ffffb7efce9bd000 > 20480 > > PAGE PHYSICAL MAPPING INDEX CNT FLAGS > ffffdd28220dc000 1883700000 0 0 1 50000000000000 > > > Thanks. > Lianbo > >> PAGE PHYSICAL MAPPING INDEX CNT FLAGS >> ffffdd28220dc000 1883700000 0 0 1 50000000000000 >> >> Signed-off-by: Tao Liu <l...@redhat.com> >> --- >> >> v1 -> v2: 1) Remove goto to print task context and vmlist. >> 2) Update commit log to show the change. >> >> --- >> memory.c | 4 ++++ >> 1 file changed, 4 insertions(+) >> >> diff --git a/memory.c b/memory.c >> index 7339f0c..9ab5781 100644 >> --- a/memory.c >> +++ b/memory.c >> @@ -13477,6 +13477,10 @@ kmem_search(struct meminfo *mi) >> * Check for a valid mapped address. >> */ >> if ((mi->memtype == KVADDR) && IS_VMALLOC_ADDR(mi->spec_addr)) { >> + if ((task = stkptr_to_task(vaddr)) && (tc = >> task_to_context(task))) { >> + show_context(tc); >> + fprintf(fp, "\n"); >> + } >> if (kvtop(NULL, mi->spec_addr, &paddr, 0)) { >> mi->flags = orig_flags | VMLIST_VERIFY; >> dump_vmlist(mi); >> -- >> 2.33.1 >> >> >> >> ------------------------------ >> >> Subject: Digest Footer >> >> -- >> Crash-utility mailing list >> Crash-utility@redhat.com >> https://listman.redhat.com/mailman/listinfo/crash-utility >> >> >> ------------------------------ >> >> End of Crash-utility Digest, Vol 203, Issue 41 >> ********************************************** >> -- Crash-utility mailing list Crash-utility@redhat.com https://listman.redhat.com/mailman/listinfo/crash-utility Contribution Guidelines: https://github.com/crash-utility/crash/wiki