| Message ID | 20241014203441.387560-1-iii@linux.ibm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | linux-user: Emulate /proc/self/maps under mmap_lock | expand |
Le 14/10/2024 à 22:34, Ilya Leoshkevich a écrit : > If one thread modifies the mappings and another thread prints them, > a situation may occur that the printer thread sees a guest mapping > without a corresponding host mapping, leading to a crash in > open_self_maps_2(). > > Cc: qemu-stable@nongnu.org > Fixes: 7b7a3366e142 ("linux-user: Use walk_memory_regions for open_self_maps") > Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com> > --- > linux-user/syscall.c | 4 +++- > 1 file changed, 3 insertions(+), 1 deletion(-) > > diff --git a/linux-user/syscall.c b/linux-user/syscall.c > index 1354e756941..dd2ec0712b8 100644 > --- a/linux-user/syscall.c > +++ b/linux-user/syscall.c > @@ -8151,17 +8151,19 @@ static int open_self_maps_1(CPUArchState *env, int fd, bool smaps) > { > struct open_self_maps_data d = { > .ts = get_task_state(env_cpu(env)), > - .host_maps = read_self_maps(), > .fd = fd, > .smaps = smaps > }; > > + mmap_lock(); > + d.host_maps = read_self_maps(); > if (d.host_maps) { > walk_memory_regions(&d, open_self_maps_2); > free_self_maps(d.host_maps); > } else { > walk_memory_regions(&d, open_self_maps_3); > } > + mmap_unlock(); > return 0; > } > Reviewed-by: Laurent Vivier <laurent@vivier.eu>
On 10/14/24 13:34, Ilya Leoshkevich wrote: > If one thread modifies the mappings and another thread prints them, > a situation may occur that the printer thread sees a guest mapping > without a corresponding host mapping, leading to a crash in > open_self_maps_2(). > > Cc: qemu-stable@nongnu.org > Fixes: 7b7a3366e142 ("linux-user: Use walk_memory_regions for open_self_maps") > Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com> > --- > linux-user/syscall.c | 4 +++- > 1 file changed, 3 insertions(+), 1 deletion(-) Reviewed-by: Richard Henderson <richard.henderson@linaro.org> Thanks, queued. r~
diff --git a/linux-user/syscall.c b/linux-user/syscall.c index 1354e756941..dd2ec0712b8 100644 --- a/linux-user/syscall.c +++ b/linux-user/syscall.c @@ -8151,17 +8151,19 @@ static int open_self_maps_1(CPUArchState *env, int fd, bool smaps) { struct open_self_maps_data d = { .ts = get_task_state(env_cpu(env)), - .host_maps = read_self_maps(), .fd = fd, .smaps = smaps }; + mmap_lock(); + d.host_maps = read_self_maps(); if (d.host_maps) { walk_memory_regions(&d, open_self_maps_2); free_self_maps(d.host_maps); } else { walk_memory_regions(&d, open_self_maps_3); } + mmap_unlock(); return 0; }
If one thread modifies the mappings and another thread prints them, a situation may occur that the printer thread sees a guest mapping without a corresponding host mapping, leading to a crash in open_self_maps_2(). Cc: qemu-stable@nongnu.org Fixes: 7b7a3366e142 ("linux-user: Use walk_memory_regions for open_self_maps") Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com> --- linux-user/syscall.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)