From: Andrew Morton <akpm@linux-foundation.org>
To: mm-commits@vger.kernel.org,torvalds@linux-foundation.org,peterz@infradead.org,oleg@redhat.com,namhyung@kernel.org,mpe@ellerman.id.au,mingo@redhat.com,mhiramat@kernel.org,mark.rutland@arm.com,kan.liang@linux.intel.com,jolsa@kernel.org,irogers@google.com,alexander.shishkin@linux.intel.com,adrian.hunter@intel.com,acme@kernel.org,svens@linux.ibm.com,akpm@linux-foundation.org
Subject: + uprobes-use-vm_special_mapping-close-functionality.patch added to mm-unstable branch
Date: Wed, 04 Sep 2024 14:26:33 -0700 [thread overview]
Message-ID: <20240904212634.2603CC4CEC2@smtp.kernel.org> (raw)
The patch titled
Subject: uprobes: use vm_special_mapping close() functionality
has been added to the -mm mm-unstable branch. Its filename is
uprobes-use-vm_special_mapping-close-functionality.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/uprobes-use-vm_special_mapping-close-functionality.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Before you just go and hit "reply", please:
a) Consider who else should be cc'ed
b) Prefer to cc a suitable mailing list as well
c) Ideally: find the original patch on the mailing list and do a
reply-to-all to that, adding suitable additional cc's
*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
The -mm tree is included into linux-next via the mm-everything
branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
and is updated there every 2-3 working days
------------------------------------------------------
From: Sven Schnelle <svens@linux.ibm.com>
Subject: uprobes: use vm_special_mapping close() functionality
Date: Tue, 3 Sep 2024 09:36:28 +0200
The following KASAN splat was shown:
[ 44.505448] ================================================================== 20:37:27 [3421/145075]
[ 44.505455] BUG: KASAN: slab-use-after-free in special_mapping_close+0x9c/0xc8
[ 44.505471] Read of size 8 at addr 00000000868dac48 by task sh/1384
[ 44.505479]
[ 44.505486] CPU: 51 UID: 0 PID: 1384 Comm: sh Not tainted 6.11.0-rc6-next-20240902-dirty #1496
[ 44.505503] Hardware name: IBM 3931 A01 704 (z/VM 7.3.0)
[ 44.505508] Call Trace:
[ 44.505511] [<000b0324d2f78080>] dump_stack_lvl+0xd0/0x108
[ 44.505521] [<000b0324d2f5435c>] print_address_description.constprop.0+0x34/0x2e0
[ 44.505529] [<000b0324d2f5464c>] print_report+0x44/0x138
[ 44.505536] [<000b0324d1383192>] kasan_report+0xc2/0x140
[ 44.505543] [<000b0324d2f52904>] special_mapping_close+0x9c/0xc8
[ 44.505550] [<000b0324d12c7978>] remove_vma+0x78/0x120
[ 44.505557] [<000b0324d128a2c6>] exit_mmap+0x326/0x750
[ 44.505563] [<000b0324d0ba655a>] __mmput+0x9a/0x370
[ 44.505570] [<000b0324d0bbfbe0>] exit_mm+0x240/0x340
[ 44.505575] [<000b0324d0bc0228>] do_exit+0x548/0xd70
[ 44.505580] [<000b0324d0bc1102>] do_group_exit+0x132/0x390
[ 44.505586] [<000b0324d0bc13b6>] __s390x_sys_exit_group+0x56/0x60
[ 44.505592] [<000b0324d0adcbd6>] do_syscall+0x2f6/0x430
[ 44.505599] [<000b0324d2f78434>] __do_syscall+0xa4/0x170
[ 44.505606] [<000b0324d2f9454c>] system_call+0x74/0x98
[ 44.505614]
[ 44.505616] Allocated by task 1384:
[ 44.505621] kasan_save_stack+0x40/0x70
[ 44.505630] kasan_save_track+0x28/0x40
[ 44.505636] __kasan_kmalloc+0xa0/0xc0
[ 44.505642] __create_xol_area+0xfa/0x410
[ 44.505648] get_xol_area+0xb0/0xf0
[ 44.505652] uprobe_notify_resume+0x27a/0x470
[ 44.505657] irqentry_exit_to_user_mode+0x15e/0x1d0
[ 44.505664] pgm_check_handler+0x122/0x170
[ 44.505670]
[ 44.505672] Freed by task 1384:
[ 44.505676] kasan_save_stack+0x40/0x70
[ 44.505682] kasan_save_track+0x28/0x40
[ 44.505687] kasan_save_free_info+0x4a/0x70
[ 44.505693] __kasan_slab_free+0x5a/0x70
[ 44.505698] kfree+0xe8/0x3f0
[ 44.505704] __mmput+0x20/0x370
[ 44.505709] exit_mm+0x240/0x340
[ 44.505713] do_exit+0x548/0xd70
[ 44.505718] do_group_exit+0x132/0x390
[ 44.505722] __s390x_sys_exit_group+0x56/0x60
[ 44.505727] do_syscall+0x2f6/0x430
[ 44.505732] __do_syscall+0xa4/0x170
[ 44.505738] system_call+0x74/0x98
The problem is that uprobe_clear_state() kfree's struct xol_area, which
contains struct vm_special_mapping *xol_mapping. This one is passed to
_install_special_mapping() in xol_add_vma().
__mput reads:
static inline void __mmput(struct mm_struct *mm)
{
VM_BUG_ON(atomic_read(&mm->mm_users));
uprobe_clear_state(mm);
exit_aio(mm);
ksm_exit(mm);
khugepaged_exit(mm); /* must run before exit_mmap */
exit_mmap(mm);
...
}
So uprobe_clear_state() in the beginning free's the memory area
containing the vm_special_mapping data, but exit_mmap() uses this
address later via vma->vm_private_data (which was set in
_install_special_mapping().
Fix this by moving uprobe_clear_state() to uprobes.c and use it as
close() callback.
Link: https://lkml.kernel.org/r/20240903073629.2442754-1-svens@linux.ibm.com
Fixes: 223febc6e557 ("mm: add optional close() to struct vm_special_mapping")
Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
include/linux/uprobes.h | 1
kernel/events/uprobes.c | 39 +++++++++++++++++++-------------------
kernel/fork.c | 1
3 files changed, 20 insertions(+), 21 deletions(-)
--- a/include/linux/uprobes.h~uprobes-use-vm_special_mapping-close-functionality
+++ a/include/linux/uprobes.h
@@ -126,7 +126,6 @@ extern int uprobe_pre_sstep_notifier(str
extern void uprobe_notify_resume(struct pt_regs *regs);
extern bool uprobe_deny_signal(void);
extern bool arch_uprobe_skip_sstep(struct arch_uprobe *aup, struct pt_regs *regs);
-extern void uprobe_clear_state(struct mm_struct *mm);
extern int arch_uprobe_analyze_insn(struct arch_uprobe *aup, struct mm_struct *mm, unsigned long addr);
extern int arch_uprobe_pre_xol(struct arch_uprobe *aup, struct pt_regs *regs);
extern int arch_uprobe_post_xol(struct arch_uprobe *aup, struct pt_regs *regs);
--- a/kernel/events/uprobes.c~uprobes-use-vm_special_mapping-close-functionality
+++ a/kernel/events/uprobes.c
@@ -1482,6 +1482,25 @@ void * __weak arch_uprobe_trampoline(uns
return &insn;
}
+/*
+ * uprobe_clear_state - Free the area allocated for slots.
+ */
+static void uprobe_clear_state(const struct vm_special_mapping *sm, struct vm_area_struct *vma)
+{
+ struct xol_area *area = container_of(vma->vm_private_data, struct xol_area, xol_mapping);
+
+ mutex_lock(&delayed_uprobe_lock);
+ delayed_uprobe_remove(NULL, vma->vm_mm);
+ mutex_unlock(&delayed_uprobe_lock);
+
+ if (!area)
+ return;
+
+ put_page(area->pages[0]);
+ kfree(area->bitmap);
+ kfree(area);
+}
+
static struct xol_area *__create_xol_area(unsigned long vaddr)
{
struct mm_struct *mm = current->mm;
@@ -1500,6 +1519,7 @@ static struct xol_area *__create_xol_are
area->xol_mapping.name = "[uprobes]";
area->xol_mapping.fault = NULL;
+ area->xol_mapping.close = uprobe_clear_state;
area->xol_mapping.pages = area->pages;
area->pages[0] = alloc_page(GFP_HIGHUSER);
if (!area->pages[0])
@@ -1545,25 +1565,6 @@ static struct xol_area *get_xol_area(voi
return area;
}
-/*
- * uprobe_clear_state - Free the area allocated for slots.
- */
-void uprobe_clear_state(struct mm_struct *mm)
-{
- struct xol_area *area = mm->uprobes_state.xol_area;
-
- mutex_lock(&delayed_uprobe_lock);
- delayed_uprobe_remove(NULL, mm);
- mutex_unlock(&delayed_uprobe_lock);
-
- if (!area)
- return;
-
- put_page(area->pages[0]);
- kfree(area->bitmap);
- kfree(area);
-}
-
void uprobe_start_dup_mmap(void)
{
percpu_down_read(&dup_mmap_sem);
--- a/kernel/fork.c~uprobes-use-vm_special_mapping-close-functionality
+++ a/kernel/fork.c
@@ -1338,7 +1338,6 @@ static inline void __mmput(struct mm_str
{
VM_BUG_ON(atomic_read(&mm->mm_users));
- uprobe_clear_state(mm);
exit_aio(mm);
ksm_exit(mm);
khugepaged_exit(mm); /* must run before exit_mmap */
_
Patches currently in -mm which might be from svens@linux.ibm.com are
uprobes-use-vm_special_mapping-close-functionality.patch
reply other threads:[~2024-09-04 21:26 UTC|newest]
Thread overview: [no followups] expand[flat|nested] mbox.gz Atom feed
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20240904212634.2603CC4CEC2@smtp.kernel.org \
--to=akpm@linux-foundation.org \
--cc=acme@kernel.org \
--cc=adrian.hunter@intel.com \
--cc=alexander.shishkin@linux.intel.com \
--cc=irogers@google.com \
--cc=jolsa@kernel.org \
--cc=kan.liang@linux.intel.com \
--cc=mark.rutland@arm.com \
--cc=mhiramat@kernel.org \
--cc=mingo@redhat.com \
--cc=mm-commits@vger.kernel.org \
--cc=mpe@ellerman.id.au \
--cc=namhyung@kernel.org \
--cc=oleg@redhat.com \
--cc=peterz@infradead.org \
--cc=svens@linux.ibm.com \
--cc=torvalds@linux-foundation.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.