commit cde9eb901ccb3b5af3e501b018b90f16c53942c2 Author: Josh Hunt Date: Mon Feb 6 20:51:31 2012 -0800 compat: poll() in 32-bit applications does not handle negative timeout values properly on 64-bit kernels We have observed our 32-bit applications running on 64-bit kernels do not wait infinitely when passed a negative value for the timeout argument. Instead we see poll() returning in ~49 days or 2^32 msecs, because the timeout argument is not getting sign-extended. Implementing compat_sys_poll() to handle this case. Reported-by: Phil Lisiecki Signed-off-by: Josh Hunt Cc: diff --git a/arch/x86/syscalls/syscall_32.tbl b/arch/x86/syscalls/syscall_32.tbl index ce98e28..8407150 100644 --- a/arch/x86/syscalls/syscall_32.tbl +++ b/arch/x86/syscalls/syscall_32.tbl @@ -174,7 +174,7 @@ 165 i386 getresuid sys_getresuid16 166 i386 vm86 ptregs_vm86 sys32_vm86_warning 167 i386 query_module -168 i386 poll sys_poll +168 i386 poll sys_poll compat_sys_poll 169 i386 nfsservctl 170 i386 setresgid sys_setresgid16 171 i386 getresgid sys_getresgid16 diff --git a/fs/compat.c b/fs/compat.c index fa9d721..77bd50e 100644 --- a/fs/compat.c +++ b/fs/compat.c @@ -1611,6 +1611,12 @@ asmlinkage long compat_sys_pselect6(int n, compat_ulong_t __user *inp, sigsetsize); } +asmlinkage long compat_sys_poll(struct pollfd __user *ufds, unsigned int nfds, + int timeout_msecs) +{ + return sys_poll(ufds, nfds, timeout_msecs); +} + asmlinkage long compat_sys_ppoll(struct pollfd __user *ufds, unsigned int nfds, struct compat_timespec __user *tsp, const compat_sigset_t __user *sigmask, compat_size_t sigsetsize) diff --git a/include/linux/compat.h b/include/linux/compat.h index 41c9f65..66e61e0 100644 --- a/include/linux/compat.h +++ b/include/linux/compat.h @@ -433,6 +433,8 @@ asmlinkage long compat_sys_pselect6(int n, compat_ulong_t __user *inp, compat_ulong_t __user *exp, struct compat_timespec __user *tsp, void __user *sig); +asmlinkage long compat_sys_poll(struct pollfd __user *ufds, unsigned int nfds, + int timeout_msecs); asmlinkage long compat_sys_ppoll(struct pollfd __user *ufds, unsigned int nfds, struct compat_timespec __user *tsp,